perf(webui): bound the transcript — containment, block flow, windowing

The remaining steady-state cost after the wedge-proofing pass was
structural: every row of an unbounded transcript participated in every
layout, and full re-renders rebuilt all of it.

CSS pair (shared scroller + the ui/static duplicate):
- The messages scroller is BLOCK flow, not a column flexbox — flex
  relayouts all items when the streaming row's height changes, O(rows)
  per token; block flow dirties only the tail. The old per-child
  flex-shrink pin (and the min-height:auto squish hazard it suppressed)
  goes with it; inter-row rhythm moves to a sibling margin.
- overflow-anchor: none — the pane owns bottom pinning, and native
  anchoring kept re-selecting an anchor inside the innerHTML-replaced
  live bubble every frame.
- content-visibility: auto with contain-intrinsic-size: auto estimates
  on .msg (80px) and .conv-batch (200px) rows, exempting the last two
  children so the live tail never toggles skip-state mid-stream. The
  `auto` keyword memoizes each row's rendered size, keeping scrollHeight
  and the bottom pin stable once painted.

Transcript windowing (interactive pane):
- Full re-renders paint the most recent 300 messages, cut FORWARD to a
  user-turn boundary so an assistant tool_calls message is never split
  from the tool results that anchor to it. Hidden content sits behind a
  "Load earlier messages" pager; each click grows the window a step and
  refetches, restoring the scroll anchor by scrollHeight delta (the
  rAF pin re-checks the near-bottom flag at fire time, so no
  suppression is needed). Rewind/edit turn math is tail-relative and
  unaffected — pinned as such.
- Live appends are bounded at the idle edge: past 900 rendered rows the
  oldest rows are trimmed (again to a turn boundary), only while pinned
  to the bottom — a scrolled-up user is reading the rows a trim would
  remove. Trimmed content stays in /history and returns through the
  pager; detached agent-card entries are swept.

The perf page gains ?window= (and the runner --perf-extra) so windowing
and containment effects can be isolated.

Measured (n=3000 history + 20-turn storm; baseline -> previous branch
-> this change): full replay 1060ms -> 238ms -> 28ms windowed / 107ms
with the window grown to the full transcript; longtasks during the run
6/1080ms -> 4/495ms -> none windowed / 4/205ms unwindowed; per-turn
live-storm cost at n=3000 now equals n=300 (~220ms harness floor) even
with all 25k nodes live — the transcript-size tax is gone. Known
degraded-mode cost: the chunk path at a fully-grown window measures
~1017ms vs the 833ms floor; the shipped windowed config sits at the
floor.

.github/workflows/ci.yml

@@ -14,8 +14,8 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         with:
           python-version: "3.14"
       - run: pip install pre-commit
@@ -25,8 +25,8 @@ jobs:
   typecheck:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         with:
           python-version: "3.14"
       - run: pip install mypy
@@ -35,12 +35,15 @@ jobs:
 
   test:
     runs-on: ubuntu-latest
+    # Cap a hung run at 20 min instead of riding GitHub's 6-hour default
+    # (a flaky-hang run otherwise streams -v output for hours).
+    timeout-minutes: 20
     strategy:
       matrix:
         python-version: ["3.11", "3.12", "3.13"]
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         with:
           python-version: ${{ matrix.python-version }}
       # Node is required by tests/test_renderer_js.py — without
@@ -51,7 +54,10 @@ jobs:
         with:
           node-version: "24"
       - run: pip install -e ".[test]"
-      - run: pytest tests/ -m "not live" --cov=turnstone --cov-report=term-missing --cov-report=xml -q
+      # -v lists each test id as it starts (pytest prints the nodeid at
+      # logstart), so a hang names the culprit on the last line instead of
+      # riding the job timeout with only a trail of "..." dots.
+      - run: pytest tests/ -m "not live" --cov=turnstone --cov-report=term-missing --cov-report=xml -v
       - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
         if: always()
         with:
@@ -60,6 +66,7 @@ jobs:
 
   test-postgres:
     runs-on: ubuntu-latest
+    timeout-minutes: 20
     services:
       postgres:
         image: postgres:18
@@ -75,23 +82,23 @@ jobs:
           --health-timeout=5s
           --health-retries=5
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         with:
           python-version: "3.14"
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: "24"
       - run: pip install -e ".[test]"
-      - run: pytest tests/ -m "not live" --storage-backend=postgresql -q
+      - run: pytest tests/ -m "not live" --storage-backend=postgresql -v
         env:
           TURNSTONE_TEST_PG_URL: postgresql+psycopg://postgres:postgres@localhost:5432/turnstone_test
 
   wheel-completeness:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         with:
           python-version: "3.14"
       - run: pip install build
@@ -106,9 +113,16 @@ jobs:
             | grep -v '\.py$' | grep -v '\.dist-info' | grep -v '\.pyc' | grep -v '^File$' \
             | sort)
 
-          # Files intentionally excluded from the wheel (one per line)
+          # Files intentionally excluded from the wheel (one per line).
+          # The vllm-litellm/ deploy example ships in the repo, not the wheel
+          # (you clone the repo to run it; the package doesn't reference it).
           ALLOW="
           turnstone/core/storage/migrations/script.py.mako
+          turnstone/deploy/vllm-litellm/.env.example
+          turnstone/deploy/vllm-litellm/README.md
+          turnstone/deploy/vllm-litellm/docker-compose.yml
+          turnstone/deploy/vllm-litellm/gemma.Dockerfile
+          turnstone/deploy/vllm-litellm/litellm-config.yaml
           "
 
           MISSING=$(comm -23 <(echo "$SOURCE") <(echo "$WHEEL") \
@@ -132,12 +146,12 @@ jobs:
           /tmp/smoke/bin/turnstone-console --help
           /tmp/smoke/bin/turnstone-admin --help
           /tmp/smoke/bin/turnstone-channel --help
-          /tmp/smoke/bin/turnstone-bootstrap --help
+          /tmp/smoke/bin/turnstone-doctor --help
 
   lock-check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
       - uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
         with:
           uv-version: "0.9.18"
@@ -146,11 +160,11 @@ jobs:
   security:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
       - uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
         with:
           uv-version: "0.9.18"
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         with:
           python-version: "3.14"
       - run: uv sync --frozen --all-extras
@@ -174,7 +188,7 @@ jobs:
       run:
         working-directory: sdk/typescript
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: "24"

.github/workflows/claude-code-review.yml

@@ -0,0 +1,46 @@
+name: Claude Code Review
+
+on:
+  pull_request:
+    types: [opened, synchronize, ready_for_review, reopened]
+    # Optional: Only run on specific file changes
+    # paths:
+    #   - "src/**/*.ts"
+    #   - "src/**/*.tsx"
+    #   - "src/**/*.js"
+    #   - "src/**/*.jsx"
+
+jobs:
+  claude-review:
+    if: github.event.pull_request.head.repo.full_name == github.repository
+    # Optional: Filter by PR author
+    # if: |
+    #   github.event.pull_request.user.login == 'external-contributor' ||
+    #   github.event.pull_request.user.login == 'new-developer' ||
+    #   github.event.pull_request.author_association == 'FIRST_TIME_CONTRIBUTOR'
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write # post the review + inline comments
+      issues: read
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code Review
+        id: claude-review
+        uses: anthropics/claude-code-action@6c0083bb7289c31716797a039b6367b3079cc46e # v1
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          allowed_bots: 'renovate[bot]' # let Renovate PRs get reviewed
+          plugin_marketplaces: 'https://github.com/anthropics/claude-code.git'
+          plugins: 'code-review@claude-code-plugins'
+          prompt: '/code-review:code-review ${{ github.repository }}/pull/${{ github.event.pull_request.number }}'
+          # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
+          # or https://code.claude.com/docs/en/cli-reference for available options
+

.github/workflows/claude.yml

@@ -0,0 +1,63 @@
+name: Claude Code
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  issues:
+    types: [opened, assigned]
+  pull_request_review:
+    types: [submitted]
+
+jobs:
+  claude:
+    if: |
+      (
+        github.event_name == 'issue_comment' &&
+        contains(github.event.comment.body, '@claude') &&
+        contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.comment.author_association)
+      ) || (
+        github.event_name == 'pull_request_review_comment' &&
+        contains(github.event.comment.body, '@claude') &&
+        contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.comment.author_association)
+      ) || (
+        github.event_name == 'pull_request_review' &&
+        contains(github.event.review.body, '@claude') &&
+        contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.review.author_association)
+      ) || (
+        github.event_name == 'issues' &&
+        (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')) &&
+        contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.issue.author_association)
+      )
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write # post comments/reviews when @-mentioned on a PR
+      issues: write # post comments when @-mentioned on an issue
+      id-token: write
+      actions: read # Required for Claude to read CI results on PRs
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code
+        id: claude
+        uses: anthropics/claude-code-action@6c0083bb7289c31716797a039b6367b3079cc46e # v1
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+
+          # This is an optional setting that allows Claude to read CI results on PRs
+          additional_permissions: |
+            actions: read
+
+          # Optional: Give a custom prompt to Claude. If this is not specified, Claude will perform the instructions specified in the comment that tagged it.
+          # prompt: 'Update the pull request description to include a summary of changes.'
+
+          # Optional: Add claude_args to customize behavior and configuration
+          # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
+          # or https://code.claude.com/docs/en/cli-reference for available options
+          # claude_args: '--allowed-tools Bash(gh pr *)'
+

.github/workflows/docker-publish.yml

@@ -7,7 +7,9 @@ on:
 
 concurrency:
   group: docker-${{ github.event.workflow_run.head_sha }}
-  cancel-in-progress: true
+  # Never cancel mid-push: an interrupted multi-tag push can leave the
+  # registry with a partial tag set (e.g. :latest moved, :stable not).
+  cancel-in-progress: false
 
 permissions:
   contents: read
@@ -19,15 +21,24 @@ env:
 
 jobs:
   docker:
+    # Same gate as publish.yml: workflow_run fires for every CI completion
+    # (including fork and same-repo PR runs) with this repo's token and
+    # packages:write.  Only same-repo tag pushes may publish images; CI's
+    # push trigger matches main/stable/* and v* tags, so a head_branch
+    # starting with "v" is necessarily a tag run.
     if: >-
       github.event.workflow_run.conclusion == 'success' &&
-      github.event.workflow_run.head_repository.full_name == github.repository
+      github.event.workflow_run.event == 'push' &&
+      github.event.workflow_run.head_repository.full_name == github.repository &&
+      startsWith(github.event.workflow_run.head_branch, 'v')
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
           fetch-depth: 0
+          # The docker build only reads the tree; keep the token out of it.
+          persist-credentials: false
 
       - name: Resolve release tag
         id: tag
@@ -72,7 +83,7 @@ jobs:
 
       - name: Build and push
         if: steps.tag.outputs.skip == 'false'
-        uses: docker/build-push-action@f9f3042f7e2789586610d6e8b85c8f03e5195baf # v7
+        uses: docker/build-push-action@53b7df96c91f9c12dcc8a07bcb9ccacbed38856a # v7
         with:
           context: .
           push: true

.github/workflows/publish.yml

@@ -7,7 +7,9 @@ on:
 
 concurrency:
   group: publish-${{ github.event.workflow_run.head_sha }}
-  cancel-in-progress: true
+  # Never cancel a publish mid-upload: a half-uploaded release (sdist up,
+  # wheel missing) cannot be re-run cleanly because PyPI rejects duplicates.
+  cancel-in-progress: false
 
 permissions:
   contents: write
@@ -15,14 +17,26 @@ permissions:
 
 jobs:
   publish:
-    if: github.event.workflow_run.conclusion == 'success'
+    # workflow_run fires for EVERY CI completion — including CI runs for
+    # pull_requests from forks — and always executes here with this repo's
+    # secrets, tokens, and the pypi environment.  Gate to same-repo tag
+    # pushes only: CI's push trigger matches branches main/stable/* and
+    # tags v*, so a head_branch starting with "v" is necessarily a tag run.
+    if: >-
+      github.event.workflow_run.conclusion == 'success' &&
+      github.event.workflow_run.event == 'push' &&
+      github.event.workflow_run.head_repository.full_name == github.repository &&
+      startsWith(github.event.workflow_run.head_branch, 'v')
     runs-on: ubuntu-latest
     environment: pypi
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
           fetch-depth: 0
+          # python -m build executes the tree's build backend; don't leave
+          # the contents:write token sitting in .git/config while it runs.
+          persist-credentials: false
 
       - name: Resolve release tag
         id: tag
@@ -36,7 +50,7 @@ jobs:
             echo "skip=false" >> "$GITHUB_OUTPUT"
           fi
 
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
         if: steps.tag.outputs.skip == 'false'
         with:
           python-version: "3.14"
@@ -49,7 +63,7 @@ jobs:
 
       - name: Create GitHub Release
         if: steps.tag.outputs.skip == 'false'
-        uses: softprops/action-gh-release@b4309332981a82ec1c5618f44dd2e27cc8bfbfda # v3
+        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3
         with:
           tag_name: ${{ steps.tag.outputs.tag }}
           generate_release_notes: true

.github/workflows/understone-example.yml

@@ -0,0 +1,42 @@
+name: Understone example
+
+# The door-game example is a standalone package with no dependency on
+# turnstone core, and the root test suite does not collect it
+# (testpaths=["tests"]). Without this workflow its suite never runs in CI.
+# Path-filtered so it only runs when the example (or this workflow) changes.
+
+on:
+  push:
+    branches: [main, "stable/*"]
+    paths:
+      - "examples/door-game/**"
+      - ".github/workflows/understone-example.yml"
+  pull_request:
+    branches: [main, "stable/*"]
+    paths:
+      - "examples/door-game/**"
+      - ".github/workflows/understone-example.yml"
+
+permissions:
+  contents: read
+
+jobs:
+  understone:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: examples/door-game
+    strategy:
+      matrix:
+        # Floor and ceiling of the example's requires-python (>=3.11).
+        python-version: ["3.11", "3.13"]
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6
+        with:
+          python-version: ${{ matrix.python-version }}
+      - run: pip install -e ".[test,dev]"
+      - run: pytest tests/ -q
+      - run: ruff check .
+      - run: ruff format --check .
+      - run: mypy understone/

.github/workflows/vendor-js.yml

@@ -25,22 +25,43 @@ permissions:
 
 jobs:
   vendor-js:
-    if: github.actor == 'renovate[bot]' || github.event_name == 'workflow_dispatch'
+    # Same-repo PRs only: this job checks out the PR head and pushes to it
+    # with contents:write, so it must never act on a fork's branch.
+    # Gate on the PR author (immutable), not github.actor (names whoever
+    # caused the latest event, which can be someone else re-running it).
+    if: >-
+      (github.event_name == 'pull_request' &&
+       github.event.pull_request.user.login == 'renovate[bot]' &&
+       github.event.pull_request.head.repo.full_name == github.repository) ||
+      github.event_name == 'workflow_dispatch'
     runs-on: ubuntu-latest
     steps:
       - name: Resolve PR head ref
         id: ref
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          # Branch names may contain shell metacharacters; pass via env,
+          # never interpolate ${{ }} into the script body.
+          HEAD_REF: ${{ github.head_ref }}
+          PR_NUMBER: ${{ inputs.pr_number }}
         run: |
-          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
-            ref=$(gh pr view "${{ inputs.pr_number }}" --repo "${{ github.repository }}" --json headRefName -q .headRefName)
+          if [[ "$GITHUB_EVENT_NAME" == "workflow_dispatch" ]]; then
+            # The dispatch input is an arbitrary PR number; refuse fork PRs.
+            # A fork's headRefName is a bare branch name that may collide
+            # with a branch in this repo, and checkout+push would then hit
+            # that unrelated branch ("same-repo PRs only" applies here too).
+            pr_json=$(gh pr view "$PR_NUMBER" --repo "$GITHUB_REPOSITORY" --json headRefName,isCrossRepository)
+            if [[ "$(jq -r '.isCrossRepository' <<< "$pr_json")" != "false" ]]; then
+              echo "::error::PR #${PR_NUMBER} head is not a branch in this repository; refusing to complete it."
+              exit 1
+            fi
+            ref=$(jq -r '.headRefName' <<< "$pr_json")
           else
-            ref="${{ github.head_ref }}"
+            ref="$HEAD_REF"
           fi
           echo "head_ref=${ref}" >> "$GITHUB_OUTPUT"
 
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
         with:
           ref: ${{ steps.ref.outputs.head_ref }}
 

CHANGELOG.md

@@ -6,81 +6,223 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [PEP 440](https://peps.python.org/pep-0440/) for
 version numbers (`X.Y.Z`, with `X.Y.ZaN` / `bN` / `rcN` for pre-releases).
 
-Three release tracks are maintained:
+Three release tracks are maintained — the current stable, one prior
+stable, and the experimental line:
 
-- **`stable/1.4`** — patch-only (`v1.4.x`)
 - **`stable/1.5`** — patch-only (`v1.5.x`)
+- **`stable/1.6`** — patch-only (`v1.6.x`)
 - **`main`** — experimental (next major)
 
-## [Unreleased]
+## [1.6.0]
+
+The first stable release of the 1.6 line — and the first under Apache 2.0.
+
+> **⚠️ Before upgrading from 1.5.x:** 1.6.0 changes the internal
+> conversation storage schema (Alembic migration `060`, applied
+> automatically on first start). The migration converts existing
+> workstreams and attachments in place — **back up your storage before
+> upgrading** (`pg_dump` for PostgreSQL; copy the database file for
+> SQLite). Background: discussion
+> [#631](https://github.com/turnstonelabs/turnstone/discussions/631).
+
+**Breaking changes at a glance** (details in the sections below):
+`web_search` backend overhaul (Tavily/DuckDuckGo removed, `topic` →
+`category`), the `man` / `math` / `plan_agent` built-in tools and the
+plan-review protocol removed, and the body-keyed `/v1/api/command`
+endpoint replaced by path-keyed workstream verbs.
+
+### License
+
+- **Relicensed to Apache 2.0** — from BUSL-1.1, effective with this
+  release (#546, contributor assent record in #548). Versions 1.5.x and
+  earlier remain under BUSL-1.1 as shipped, and the `stable/1.5` branch
+  keeps its original LICENSE. New `NOTICE` and
+  `CONTRIBUTORS.md` files; `THIRD-PARTY-NOTICES` refreshed to match the
+  bundled library versions.
 
 ### Added
 
-- **Self-hosted SearxNG web search** — the `web_search` tool's backend for
-  local/vLLM models is now a bundled [SearxNG](https://searxng.org) service
-  (`searxng` in both compose stacks; internal docker network only, JSON API
-  enabled, rate limiter off). Two new settings configure it: `tools.searxng_url`
-  (default `http://searxng:8080`, env `TURNSTONE_SEARXNG_URL`) and
-  `tools.searxng_engines` (env `TURNSTONE_SEARXNG_ENGINES`). Commercial providers
-  (Anthropic, OpenAI) continue to use their own native server-side search and
-  never touch SearxNG; the `mcp:server:tool` backend is unchanged. A persistent
-  `searxng-cache` volume keeps its favicon/internal cache across restarts, and
-  Caddy can serve SearxNG's own web UI on a dedicated port (dev stack:
-  `https://localhost:8444`, localhost-only; production: opt-in). See
-  [docs/docker.md](docs/docker.md) for the AGPL-3.0 §13 note that applies to
-  operators who expose the bundled SearxNG publicly.
-
-- **`turnstone-admin` reads `config.toml`** — the admin CLI now honors
-  the same `[database]` section that `turnstone-server` does, with the
-  same precedence (`CLI / config.toml > TURNSTONE_DB_* env > defaults`).
-  Operators with DB credentials in `config.toml` no longer need to
-  re-export `TURNSTONE_DB_URL` before every admin invocation.  Newly
-  plumbed through to `init_storage`: `pool_size`, `sslmode`,
-  `sslrootcert`, `sslcert`, `sslkey` — previously the admin CLI
-  silently dropped these.  A new `--config PATH` flag mirrors the
-  one already on `turnstone-server`.
+- **Mid-conversation system messages** — advisories, watch results,
+  skill hints, and operator interjections are now first-class
+  `role=system` turns in the trajectory instead of ad-hoc reminder
+  envelopes. Models with native mid-conversation system support receive
+  them verbatim; for everything else they fold into a nonce-fenced
+  wrapper. The one-shot `_reminders` side-channel is gone.
+- **Self-hosted SearxNG web search** — the `web_search` backend for
+  local/vLLM models is now a bundled [SearxNG](https://searxng.org)
+  service (in both compose stacks; internal network only). Configure via
+  `tools.searxng_url` / `tools.searxng_engines`. Commercial providers
+  keep their native server-side search; the model can target a corpus by
+  passing `category` (`general`, `news`, `it`, `science`). Operators
+  exposing the bundled SearxNG publicly: see the AGPL-3.0 §13 note in
+  [docs/docker.md](docs/docker.md).
+- **Endpoint-backed reranking** — a reranker is now a per-model
+  definition (Cohere/Jina-compatible wire: vLLM, TEI, llama.cpp, or a
+  commercial endpoint), disabled by default. When configured it scores
+  `web_search` results and the BM25 retrieval surfaces (deferred tools,
+  skills, memory) behind a `tools.rerank_bm25` toggle with a relevance
+  floor; a calibration CLI (and calibrate-on-detect) tunes the floor
+  per model.
+- **Proactive memory relevance** — injected memories are selected by
+  BM25 + reranker against the recent user messages instead of recency
+  alone, and first composition defers to the first user turn so fresh
+  sessions select against a real query.
+- **Smart Approvals** — opt-in (default off): high-confidence `approve`
+  verdicts from the intent judge auto-approve the tool call instead of
+  waiting for a human, with a confidence threshold and verdict
+  bookkeeping designed so a denied or reset judge never auto-fires.
+- **Early-painted tool calls** — committed tool calls render immediately
+  as pending cards (both UIs upgrade the card in place by `call_id`)
+  instead of waiting for the judge verdict, so big parallel batches no
+  longer sit invisible during judging.
+- **Voice I/O v1** — speech-to-text and text-to-speech as model roles
+  speaking the OpenAI audio wire protocol (#618); the interactive
+  composer grows a mic button.
+- **Rewind / retry / edit-first-message** — full UX in both the
+  interactive UI and the coordinator pane, backed by shared path-keyed
+  verb handlers (#549).
+- **Workstream export** — download a conversation as OpenAI-format
+  messages JSON.
+- **Skills platform round** — `SKILL.md` ingestion learns
+  `when_to_use` / `model` / `effort` / `paths`; prompt substitution
+  supports `$ARGUMENTS`, `$N`, `$<name>`, and `${CLAUDE_*}` (#572);
+  per-skill `disable-model-invocation` and `user-invocable` flags
+  (#571); `skill` + `list_skills` unify into one dual-kind tool; new
+  `model.skills.write` permission.
+- **Coordinator hardening for small models** — workstream references in
+  coordinator tool calls are validated with did-you-mean recovery, and
+  `wait_for_workstream` fails fast with uniform `not_found` entries
+  instead of hanging on a hallucinated `ws_id`.
+- **Provider support** — Claude Fable 5 and Claude Opus 4.8; xAI/Grok
+  via the OpenAI Responses lane; vLLM reasoning-field replay completes
+  the reasoning-persistence work (#537).
+- **Cluster-by-default deployment** — the compose stack fronts
+  everything with Caddy and supports bare-metal node join; a one-line
+  `curl | bash` installer bootstraps a node; nodes with no configured
+  models boot into a degraded state instead of crash-looping; channel
+  gateways stand by when no adapter token is set.
+- **MCP OAuth tokens encrypted at rest**.
+- **`turnstone-admin` reads `config.toml`** — same `[database]` section
+  and precedence as the server (`CLI / config.toml > TURNSTONE_DB_* env
+  > defaults`), including `pool_size` and the `ssl*` knobs it previously
+  dropped; new `--config PATH` flag.
 
 ### Changed
 
+- **Conversation storage and the provider wire are rebuilt around a
+  canonical trajectory** (migration `060` — see the upgrade note).
+  Internally a conversation is now a provider-neutral `Turn` sequence
+  lowered to each provider's wire format at send time; provider-specific
+  tool-call metadata rides an opaque producer-tagged lane (replayed
+  verbatim to the producing provider, rebuilt for others); attachments
+  become content-addressed, reference-counted rows resolved at the
+  provider boundary; orphan tool-call repair happens once, at send time.
+  Wire-visible behavior is unchanged for OpenAI-compatible providers;
+  histories are preserved across the migration.
+- **The console and web UI share one L-shell** — a left glyph rail, a
+  tab bar, and a pane host now frame interactive chats, coordinator
+  sessions, dashboards, and the admin panel as tabs in a single window;
+  the standalone web UI adopts the same shell and the old split-pane
+  layout is retired. Coordinator and interactive conversations render
+  through shared `.conv-*` card builders, the rail collapses to a glyph
+  strip (remembered per browser), mobile gets an off-canvas drawer, and
+  the frontend is now ES modules end to end.
+- **Admin panel modals → the Service Hatch shelf** — all ~35 admin
+  modals are replaced by pane-scoped shelves plus a small dialog tier
+  for confirmations. Schedules gain a cron builder with a next-3-runs
+  preview endpoint, model capabilities render as an LED tile matrix, and
+  the legacy modal machinery is deleted.
+- **SSE delivery is resumable end to end** — per-workstream ring buffer
+  with `Last-Event-ID` replay (cap raised 2,000 → 50,000), fresh-connect
+  and reconnect unified on one event-id cursor (in-flight tool batches
+  included), persisted `last_error` replays on connect, the console
+  proxy forwards `Last-Event-ID`, and panes close their connections on
+  `beforeunload` to stop multi-pane refresh from exhausting the
+  browser's per-host connection cap (#539).
+- **Workstream verbs are path-keyed** *(BREAKING)* — `rewind` / `retry`
+  / `edit-first-message` live at
+  `/v1/api/workstreams/{ws_id}/<verb>` alongside the other session
+  verbs; the body-keyed `/v1/api/command` endpoint is removed (#549).
+- **`/history` is projected server-side** — both UIs consume the same
+  REST-first wire shape instead of re-deriving it client-side.
+- **Saved workstreams & coordinators: card grid → sortable table** with
+  model/skill/context columns, pagination, and a unified selector across
+  both dashboards.
 - **`tools.web_search_backend` accepted values** *(BREAKING)* — now `""`
-  (auto), `"searxng"`, or `"mcp:server:tool"`. The old `"tavily"` and `"ddg"`
-  values are gone; a config still set to either disables web search and logs a
-  warning. Auto-detect resolves to SearxNG when `searxng_url` is set, otherwise
-  no client (the `web_search` tool is dropped for models without native search).
-- **`web_search` tool: `topic` → `category`** *(BREAKING)* — the LLM-facing
-  parameter is renamed and its values are now `general` (default), `news`, `it`
-  (code/tech), or `science`, mapped to SearxNG categories so the model can target
-  the right corpus. The Tavily-era `finance` topic (no SearxNG equivalent) is gone.
+  (auto), `"searxng"`, or `"mcp:server:tool"`. The old `"tavily"` and
+  `"ddg"` values are gone; a config still set to either disables web
+  search and logs a warning. Auto-detect resolves to SearxNG when
+  `searxng_url` is set.
+- **`web_search` tool: `topic` → `category`** *(BREAKING)* — renamed
+  LLM-facing parameter; values map to SearxNG categories. The Tavily-era
+  `finance` topic is gone.
+- **Core install includes what most deployments use** — `anthropic`,
+  `postgres`, `console`, and `tls` are core dependencies rather than
+  extras.
+- **NODES table → bottom-bar node picker** in the console.
+
+### Fixed
+
+- **Cluster mTLS actually survives operations** — certificate identity
+  keys on the advertised host rather than the container ID, renewals are
+  scoped per node, reloaded certs hot-swap into the live SSL context,
+  and healthchecks/boot retries are mTLS-aware.
+- **Intent-verdict lifecycle** — history replay ships risk-none verdict
+  rows (live/replay parity), late verdicts persist as `superseded` for
+  the audit trail instead of vanishing, bulk verdict insert tolerates
+  per-row conflicts, and cancel-on-approval honors its run-to-completion
+  contract.
+- **Usage accounting** — dashboard totals were under-counting; auxiliary
+  LLM spend (judge, rerank, memory) is now recorded.
+- **Concurrent first-boot migrations** no longer deadlock on the
+  advisory lock.
+- **Output renderer** — single-`$` inline math no longer false-positives
+  in prose; `strip_html` preserves block structure and drops a ReDoS
+  risk.
+- **Model registry** orders versions numerically (no more `1.10 < 1.9`
+  selection).
 
 ### Removed
 
-- **Tavily and DuckDuckGo `web_search` backends** *(BREAKING)* — replaced by the
-  bundled self-hosted SearxNG service (see Added). Removed: the
-  `tools.tavily_api_key` setting, the `$TAVILY_API_KEY` env var, the
-  `[api].tavily_key` config key, and the `ddg` install extra (the `ddgs`
-  dependency). Migration: use the bundled SearxNG (it ships in the compose stacks
-  by default) or point `TURNSTONE_SEARXNG_URL` at an existing instance. No
-  database migration required.
-- **`man`, `math`, and `plan_agent` built-in tools removed** — `man` and
-  `math` duplicated capabilities already available through `bash`; `plan_agent`
-  is better expressed as a `task_agent` running a planning skill.  Removing
-  them simplifies the tool surface and cuts per-call token cost.  This release
-  also removes: the `math` sandbox executor (`turnstone.core.sandbox`) and the
-  `[sandbox]` extra's role for it; the read-only `AGENT_TOOLS` sub-agent tool
-  set and the `agent` tool-metadata key; the plan-review protocol
-  (`/v1/api/plan` endpoint, `plan_review`/`plan_resolved` SSE events, the
-  `on_plan_review` SDK/UI hook); and the `model.plan_alias` /
-  `model.plan_effort` ConfigStore settings (and the corresponding
-  `[model].plan_model` / `[model].plan_effort` config.toml knobs).
-  **Breaking change** on the experimental 1.6 line.  Interactive built-in tool
-  count moves from 19 → 16; `TASK_AGENT_TOOLS` from 13 → 11.
+- **Tavily and DuckDuckGo `web_search` backends** *(BREAKING)* —
+  replaced by the bundled SearxNG service. Removed:
+  `tools.tavily_api_key`, `$TAVILY_API_KEY`, `[api].tavily_key`, and the
+  `ddg` install extra. Point `TURNSTONE_SEARXNG_URL` at an existing
+  instance or use the bundled one; no database migration required.
+- **`man`, `math`, and `plan_agent` built-in tools** *(BREAKING)* —
+  `man`/`math` duplicated `bash`; planning is better expressed as a
+  `task_agent` running a planning skill. Also removed: the `math`
+  sandbox executor, the read-only `AGENT_TOOLS` sub-agent set, the
+  plan-review protocol (`/v1/api/plan`, `plan_review`/`plan_resolved`
+  SSE events, `on_plan_review` hooks), and the `model.plan_*` settings.
+  Interactive built-in tool count: 19 → 16.
+- **`stable/1.4` track retired** — the maintenance policy is now the
+  current stable plus one prior (`stable/1.6` + `stable/1.5` as of this
+  release). 1.4's final release was `v1.4.0`; its tags and released
+  artifacts remain available, under BUSL-1.1 as shipped.
 
 ### Security
 
-- **Permissive `config.toml` now warns** — `turnstone.core.config.load_config`
-  logs a single warning when the resolved config file is group- or
-  world-readable (any bit in `0o077`).  DB password and TLS key paths
-  live in `[database]`; operators usually want the file at `0600`.
+- **Zero direct-HTML frontend** — every `innerHTML` sink across the
+  console and web UI is replaced with DOM construction or `setSafeHtml`,
+  inline handlers became delegated bindings, and CI lints pin the
+  invariant (plus `var`-free and const-reassign checks) across all
+  swept bundles.
+- **Output guard grows an LLM stage** — merged with the heuristics as
+  escalate-only (an LLM verdict can raise but never lower a heuristic
+  positive), with annotated findings, a capability gate, and hardening
+  against domain-camouflaged injection (#560, #573).
+- **One trust-fence primitive** — operator and judge envelopes share a
+  nonce-fenced wrapper (64-bit nonces, host-escaping); the output guard
+  flags nonce forgery, and skill hints no longer echo model-controlled
+  filter values into trusted text.
+- **RBAC** — built-in role overrides get an editor, and several
+  under-enforced permission gates are tightened (#585).
+- **Permissive `config.toml` warns** — a single startup warning when the
+  resolved config file is group- or world-readable; operators usually
+  want `0600`.
+- **Dependency floors** — `starlette>=1.0.1` (PYSEC-2026-161 host-header
+  path injection) and `aiohttp>=3.14.0` (security release).
 
 ## [1.5.17]
 

CONTRIBUTING.md

@@ -56,4 +56,4 @@ Open an issue at https://github.com/turnstonelabs/turnstone/issues with:
 ## License
 
 By contributing, you agree that your contributions will be licensed under the
-project's [Business Source License 1.1](LICENSE).
+project's [Apache License 2.0](LICENSE).

CONTRIBUTORS.md

@@ -0,0 +1,13 @@
+# Contributors
+
+Turnstone is written and maintained by Patrick Buckley
+([@eous](https://github.com/eous)).
+
+The following people have contributed code to the project — thank you:
+
+- Burhan ([@Burhan-Q](https://github.com/Burhan-Q))
+- chrismuzyn ([@chrismuzyn](https://github.com/chrismuzyn))
+- daoxley ([@daoxley](https://github.com/daoxley))
+- Robert DeAngelis ([@OriginalOrangeXD](https://github.com/OriginalOrangeXD))
+- William ([@sillyWillieBilly](https://github.com/sillyWillieBilly))
+- [@pizzaandcheese](https://github.com/pizzaandcheese)

Dockerfile

@@ -8,7 +8,7 @@ FROM python:3.14-slim
 LABEL org.opencontainers.image.title="turnstone" \
       org.opencontainers.image.description="Multi-node AI orchestration platform"
 
-COPY --from=ghcr.io/astral-sh/uv:0.11.19 /uv /usr/local/bin/uv
+COPY --from=ghcr.io/astral-sh/uv:0.11.26 /uv /usr/local/bin/uv
 
 # Remove the slim image's man page exclusion so man-db has actual content
 RUN rm -f /etc/dpkg/dpkg.cfg.d/docker
@@ -17,8 +17,10 @@ RUN rm -f /etc/dpkg/dpkg.cfg.d/docker
 # ripgrep is the preferred backend for the search tool — natively bounds
 # per-line, per-file, and per-filesize so pathological inputs (minified
 # bundles, training-data JSONL with multi-MB single records) can't OOM us.
+# ffmpeg transcodes omni STT uploads (browser webm/opus) to the 16 kHz mono
+# WAV the omni chat-audio lane decodes.
 RUN apt-get update && apt-get upgrade -y && apt-get install -y --no-install-recommends \
-    libpq5 git curl jq man-db manpages procps file ripgrep \
+    libpq5 git curl jq man-db manpages procps file ripgrep ffmpeg \
     && rm -rf /var/lib/apt/lists/*
 
 # Node.js LTS (for npx-based MCP servers like @modelcontextprotocol/server-github)
@@ -33,7 +35,7 @@ RUN useradd --create-home --shell /bin/bash turnstone
 WORKDIR /app
 
 # Install dependencies first (cached layer — only re-runs when deps change)
-COPY pyproject.toml uv.lock README.md LICENSE ./
+COPY pyproject.toml uv.lock README.md LICENSE NOTICE THIRD-PARTY-NOTICES ./
 RUN uv sync --frozen --no-install-project --no-dev \
     --no-compile --extra all
 

HYPOTHESIS.md

@@ -0,0 +1,207 @@
+# What is a harness?
+
+*A hypothesis — not a theorem. The honest answer is a claim about **shape**: an object you can write down that says what a harness is and, just as precisely, the guarantee it cannot carry for free.*
+
+Most descriptions of an agent framework are a feature list. This is an attempt at a definition.
+
+---
+
+## The claim
+
+*Informal.* A harness is a **stopped, deterministically-controlled Markov process on task-state, closed around a stopped autoregressive process on context-space, driven by a learned model kernel** — a deterministic controller in closed loop with a stochastic learned plant.
+
+*In plain terms.* The **harness** is the whole governed loop: a deterministic **shell** you write — build the prompt, authorize an action, fold the response back into state — wrapped around a black-box stochastic model kernel (the **plant**, $M_W$) and the environment its actions touch, looped until it halts in $H$. The shell is deterministic, $M_W$ is not, and everything below makes that split precise.
+
+*Formal — the objects.* A harness is a tuple $\mathcal{H} = (\mathcal{S}, \mathcal{C}, \mathcal{Y}, \mathcal{A}, \mathcal{E}, \pi, M_W, \gamma, Q_E, \rho, H, H_{\mathrm{ok}}, B)$ over **standard Borel** spaces (concretely: the *controlled* state is standard Borel by construction — token sequences, finite config maps, bounded counters and ledgers, finite tuples of real vectors — and the model/environment coordinates are inherited as such whenever they serialize to a Polish space; the assumption is roomier than it looks — even a belief-state coordinate valued in $\mathcal{P}(X)$ survives, since $\mathcal{P}(X)$ is Polish for Polish $X$ — and fails only for a genuinely non-separable coordinate, an uncountable product $\sigma$-algebra being the canonical hazard, which this construction avoids): a deterministic lowering $\pi:\mathcal{S}\to\mathcal{C}$; a stochastic model-run kernel $M_W(c, dy)$ into a readout space $\mathcal{Y}$ (which includes the parse-failure $\bot$, so $M_W$ and $\gamma$ are total over it); a deterministic **authorization gate** $\gamma:\mathcal{S}\times\mathcal{Y}\to\mathcal{A}_{\bot}$ that validates the model's parsed readout into an authorized action in $\mathcal{A}$ or rejects it as $\bot$ (parsing itself lives inside $M_W$ — realized as the readout $R$ of the specialization below); a stochastic environment/tool kernel $Q_E:\mathcal{S}\times\mathcal{A}_{\bot}\rightsquigarrow\mathcal{E}$ on the authorized action (rejection included, with $Q_E(s,\bot,\cdot)=\delta_{e_0}$ for a distinguished no-op response $e_0\in\mathcal{E}$); and a deterministic verify-and-fold-back map $\rho:\mathcal{S}\times\mathcal{Y}\times\mathcal{A}_{\bot}\times\mathcal{E}\to\mathcal{S}$.
+
+*Terminal structure.* The terminal set is an absorbing halt set $H\subseteq\mathcal{S}$ (the daemon "ready-state" recurrence of the note below is a separate, non-absorbing object) with accepting subset $H_{\mathrm{ok}}\subseteq H$; separately, a bad set $B\subseteq\mathcal{S}$ ($B\cap H_{\mathrm{ok}}=\varnothing$) marks the unsafe states for reach-avoid, possibly entered before any halt; hitting times are $\tau_A=\inf\{n\ge 0:s_n\in A\}$, and $\tau_H$ is a stopping time for the natural filtration.
+
+*The outer kernel.* The induced outer transition kernel, for $s\notin H$, is
+
+$$T(s, A) = \int_{\mathcal{Y}}\!\int_{\mathcal{E}} \mathbf{1}_A\!\big(\rho(s, y, \gamma(s,y), e)\big)\; Q_E\big(s, \gamma(s,y), de\big)\; M_W(\pi(s), dy), \qquad T(s,A)=\mathbf{1}_A(s)\ \text{ for } s\in H,$$
+
+and the harness runs $s_{n+1} \sim T(s_n)$ from an initial $s_0 \sim \mu_0$ until $\tau_H = \inf\{n : s_n \in H\}$. Because $\pi, \gamma, \rho, H$ are deterministic they contribute no integration variable of their own — they appear as measurable transformations inside the integrand (the pushforward), not literally outside it — so the controller injects no randomness, and every coin is inherited from $M_W$ and $Q_E$. (The earlier shorthand $T = \rho \circ (M_W \circ \pi, E)$ is suggestive but ill-typed — $M_W$ returns a *law*, while $\rho$ consumes a *sample* together with the prior state $s$; the integral is what the shorthand meant.)
+
+*Fail-closed.* The gate $\gamma$ is what makes **fail-closed** a property, not just a name: model output is an *untrusted proposal*, and $\gamma(s,y)=\bot$ forces a no-op environment response ($Q_E(s,\bot,\cdot)=\delta_{e_0}$) — so a malformed or unauthorized tool call is rejected *before* it can act, not validated after its side effects have landed. Fail-closed is then the property that a rejected proposal causes *no unauthorized side effect* and lands in a **safe, non-bad** set ($\rho(s,y,\bot,e_0)\notin B$): a non-accepting terminal $H\setminus H_{\mathrm{ok}}$ in the strict case, or a safe non-terminal state when the spec retries. And $\rho$ must validate the tool *response* $e$, not only the proposal that $\gamma$ already gated: a malformed or adversarial response $e$ is caught at fold-back, not just at the gate. But response-validation has a hard limit: $\rho$ can reject a bad tool *response*, yet it cannot undo side effects an *authorized* action already caused — so $\gamma$, not $\rho$, is the last line before irreversible effects, and anything irreversible must be gated at authorization. The boundary is also only real if raw model output reaches *no* sink — tool, logger, browser, or remote call — before $\gamma$; any pre-authorization escape bypasses the gate. The user-visible final response and any logging are themselves effects, and the rule binds *model-authored* bytes: they reach a sink either as an authorized action through $\gamma$, or only after an accepted halt in $H_{\mathrm{ok}}$. Shell-*templated* text — a refusal notice, a cancellation report reading the ledger — is controller output, outside $\gamma$'s jurisdiction, and may accompany any halt (a template that *interpolates* model-authored fragments inherits the model's label — the appendix's meet rule — and those bytes are gated like any others); the invariant is that raw model text never reaches a sink ungated, not that failed runs die silent.
+
+*The harness invariants.* These are the invariants that make $\mathcal{H}$ a *harness* and not merely a controlled Markov process with a learned kernel inside: the model sees only $\mathcal{C}$, never full $\mathcal{S}$; its outputs are proposals, not actions; a deterministic capability boundary $\gamma$ gates every side effect; and the *terminal* set $H$ splits into accepting ($H_{\mathrm{ok}}$) and non-accepting ($H\setminus H_{\mathrm{ok}}$ — safe refusals outside $B$, and wrong or bad halts possibly in $B$), while the bad set $B$ is a *separate* unsafe set — possibly absorbing, possibly entered mid-run before any halt — against which $\tau_B$ is measured for reach-avoid. Two notes keep the invariants honest. They are *signature*, not strength: a $\gamma$ that authorizes everything still satisfies the tuple, as a trivial group satisfies the group axioms — the definition admits degenerate harnesses, and fail-closed, provenance isolation, and the certificates below are properties a particular harness *earns*, not gifts of the signature. And the first invariant has a sharper, two-sided form: $\pi$ is the *only* channel from state to model — the confidentiality floor lives at what $\pi$ must never lower (credentials, other principals' data) — exactly as $\gamma$ is the only channel from model output to effect, where the injection bounds live; exfiltration is therefore cut at either chokepoint, never lowered or never emitted (the gate refusing the read whose URL is the payload is the emission-side cut). One chokepoint out of the state, one into the world; a bypass of either is the same bug with the sign flipped.
+
+*Beyond the stationary kernel.* This displayed $T$ is the time-homogeneous, fixed-kernel case; for nonstationary or adversarial environments, replace $Q_E$ with a time-indexed kernel $Q_{E,n}$ — or an admissible family of kernels, or an adversary's policy — over which the robust certificate (the minimax form under *The limit*) quantifies. If that adversary conditions on history rather than only the current $(s, y)$, the history must itself live in $s$ — otherwise the object is a Markov *game* requiring further augmentation, not a Markov chain. And nonstationarity is not the environment's monopoly: a provider retraining or re-serving under a fixed endpoint name is a nonstationary $M_{W,n}$ — the table places model version *in* $s$ precisely so a version bump is a visible state change — and any measured surrogate (the $\delta$ of *The limit*) is calibrated against one kernel and dies with the bump; the dashboard must be keyed to the kernel it measured.
+
+*The inner kernel.* $M_W$ is itself a stopped process, and for a decoder-only transformer it is implemented as
+
+$$M_W(c, \cdot) = \mathrm{Law}\big(R(z_{\tau})\big), \quad z_t = (c_t, b_t, m_t), \quad v \sim K_W(c_t, \cdot), \quad K_W(c, v) = (U \circ \Phi_W \circ \mathrm{Emb})(c)[v], \quad c_{t+1} = \mathrm{suffix}_{\le L}(c_t\!\cdot\! v),\ \ b_{t+1} = b_t\!\cdot\! v,\ \ m_{t+1} = \mathsf{step}(m_t, v),\ \ \tau=\inf\{t:m_t\in\mathrm{Stop}\}.$$
+
+with the layer stack $\Phi_W$ on the residual stream as the (loosely) "manifold" core — formally just the learned high-dimensional residual-stream transformation, with manifold-proper reserved for the frontier. The inner state $z_t=(c_t,b_t,m_t)$ separates the model-visible window $c_t$ (the $\le L$ slice that slides) from the untruncated output buffer $b_t$ (the transcript the readout actually consumes, so truncation never loses it) and the parser/stop state $m_t$ (parser state, a token counter, and a clock, so the cap and timeout are functions of it), updated $m_{t+1}=\mathsf{step}(m_t,v)$, whose stop set $\mathrm{Stop}$ — EOS emitted, max-token cap, timeout, or parse-failure $\bot$ — forces $\tau=\inf\{t:m_t\in\mathrm{Stop}\}$ finite, making $M_W$ a genuine *probability* kernel rather than a sub-probability one completed by a cemetery output. (One honesty note on the clock: a token-count cap is a deterministic function of the run, but a *wall-clock* timeout imports infrastructure noise — server load, batching, congestion — into the kernel's coin; legitimate, a kernel may carry any randomness, but it makes the displayed $M_W$ the model *plus its serving substrate*, and the determinism audit under *How this could be wrong* must hold the clock fixed along with the samples.) The readout is total, $R : \mathcal{Z} \to \mathcal{Y}$ — a parsed tool-call, answer, or transcript, returning the parse-failure $\bot\in\mathcal{Y}$ when parsing fails; crucially $R$ is a *syntactic, verified* readout (parsing and extraction), not a semantic solver, or the $L$-wall below is void — arbitrary computation could hide in $R$ off the $\le L$ window — so $M_W(c, \cdot) = R_{\sharp}\,\mathrm{Law}(z_{\tau})$, the pushforward of the stopped-state law along $R$ (equivalently $M_W(c, A_Y) = \Pr[R(z_{\tau}) \in A_Y \mid z_0 = (c,\varnothing,m_0)]$ for a measurable $A_Y\subseteq\mathcal{Y}$); the no-truncation special case takes $\mathcal{Y}=\mathcal{C}$ with $R(c,b,m)=c$ (the window is the whole transcript), reading $c_{\tau}$ directly. The $\bot$ branch is exactly what $\gamma$ rejects fail-closed. This is a **specialization, not part of the definition**: a harness wrapped around a black-box API is still a harness, and $M_W$ may be any learned kernel. Where the weights are open, the geometry of $\Phi_W$ is where the substrate's continuity lives, and several downstream claims lean on it — but the definition does not.
+
+Two stopped processes, nested: **deterministic control over stochastic dynamics over a learned kernel.** Both loops are hitting-time processes; *some* harnesses additionally read the halt set as a fixpoint or acceptance condition — iterative refinement to self-consistency is the genuine fixpoint case, while EOS, length, and tool-call syntax are not convergence. Neither loop settles because you asked it to. (The clean inner-then-outer nesting assumes tool calls fall *between* model runs; streaming or mid-generation tool calls interleave the two loops and need a finer state machine — the nesting is then an idealization.)
+
+## Reading it
+
+| Symbol | Is |
+|---|---|
+| $\mathcal{H}$ | the harness — the whole controlled system, *not* the model |
+| $s \in \mathcal{S}$ | task-state: IR / dialect stack, tool results, plan, counters, **and every mutable interface variable** (model/tool versions, permissions, retrieved context) — only Markov *after* that augmentation |
+| $\mathcal{C},\ \mathcal{Y},\ \mathcal{A},\ \mathcal{E}$ | the **context / readout / action / effect spaces** — model-visible context $\mathcal{C}$, model readout $\mathcal{Y}$ (incl. the parse-failure $\bot$), authorized actions $\mathcal{A}$ (with $\mathcal{A}_\bot = \mathcal{A}\cup\{\bot\}$), and tool/environment effects $\mathcal{E}$ |
+| $\pi : \mathcal{S} \to \mathcal{C}$ | **lowering** — prompt construction, dialect lowering, effective-program selection (deterministic) |
+| $M_W(c, dy)$ | the **model-run kernel** (inner solver) — a stopped autoregressive process; $\Phi_W$ is the residual-stream ("manifold") core in the transformer case |
+| $Q_E(s, a, de)$ | the **environment/tool kernel** on the authorized action $a\in\mathcal{A}_{\bot}$ (with $Q_E(s,\bot,\cdot)=\delta_{e_0}$, the no-op $e_0$) — tool effects, API responses, the world (possibly adversarial) |
+| $\gamma,\ \rho$ | the deterministic **authorization gate** $\gamma:\mathcal{S}\times\mathcal{Y}\to\mathcal{A}_{\bot}$ (untrusted proposal → authorized action or $\bot$) and the **fail-closed verify-and-fold-back** $\rho:\mathcal{S}\times\mathcal{Y}\times\mathcal{A}_{\bot}\times\mathcal{E}\to\mathcal{S}$ |
+| $H,\ \tau_H$ | the **halt set** (absorbing) and the outer **halting time** — a hitting-time process, not a single pass |
+| $H_{\mathrm{ok}},\ B$ | the **accepting halts** $H_{\mathrm{ok}}\subseteq H$ (correct, successful terminals) and the **bad set** $B$ — unsafe states for reach-avoid ($B\cap H_{\mathrm{ok}}=\varnothing$), *separate* from $H$ and possibly entered mid-run before any halt |
+
+The structural fact that earns the word *controller*: $\pi$, $\gamma$, $\rho$, and the halt test are **deterministic** (and the readout $R$ too, where the transformer specialization is in play), so $\mathcal{H}$ injects no randomness of its own. Every coin is inherited from $M_W$ and $Q_E$. This split — deterministic code around a stochastic oracle — wears two names. In control-theory terms it is **controller vs. plant**: the controller is those deterministic maps; the **plant** is the learned kernel $M_W$, *plant* in its exact sense — the element with its own dynamics you steer but do not author. In engineering terms it is **shell vs. plant**: the **shell** is the entire deterministic outer harness — the control logic *plus* the external memory and tools it administers (the files, databases, vector stores below) — of which the controller is just the control-logic slice. So *shell : plant :: the part you write : the part you don't*; $M_W$ is the only thing on the right, while the environment $Q_E$ is the world the actions meet — a disturbance into the loop, not the plant. (A reader from reinforcement learning or classical control will make the opposite assignment — environment as plant, policy as controller; the inversion is deliberate: in harness engineering the element you are trying to make behave is the model, and the world is what pushes back on the attempt.) This determinism is *conditional* — on versioned code, configuration, model endpoint, and tool interfaces, and on *single-run sequencing*: concurrent runs sharing authorization state re-open a gap the per-run object cannot see (taken up under *Gate placement* in the appendix); any retry, timeout, race, or randomized routing that escapes that conditioning must be modeled explicitly as part of $Q_E$ or the controller, not waved away. The displayed $M_W(c)$ likewise freezes endpoint, version, and sampler; a routing or config change is a state-indexed kernel $M_{\kappa(s)}$ or folds into $K_C$ — the kernel must not silently depend on config the table places in $s$. More generally, control may itself be stochastic — a controller kernel $K_C(s, dc)$ over routing, sampled retries, ensemble votes, learned routers — of which the deterministic $\pi, \gamma, \rho, H$ are the Dirac special case. That case is the one worth wanting: it localizes every coin to $M_W$ and $Q_E$ and keeps the controller/plant split clean. Where control is genuinely stochastic the split does not break, it widens — fold $K_C$ into the kernel and the certificate quantifies over its randomness too. But the guarantees do not soften uniformly, and the component-to-guarantee map is worth stating because it says exactly what may be learned without loss. A learned $\pi$ — retrieval, reranking, summarization inside the lowering — costs only *semantic adequacy*, under one factorization: $\pi$ splits into a deterministic **never-lower filter** — the redaction that keeps credentials and other principals' data out of $\mathcal{C}$ — composed with learned selection, and only the selection may soften, or the confidentiality floor of the invariants note becomes a probability. With the filter Dirac, no-unauthorized-effect is $\gamma$'s property alone, and the reach-avoid certificate survives too, so long as the provenance partition of *The limit* holds. A learned $\gamma$ or $\rho$ costs the thing itself — authorization and ledger integrity are exactly the properties that must stay Dirac, or "no unauthorized effect" and "the ledger is what happened" become probabilities. So the minimal deterministic core is $\{\gamma, \rho, H\}$ plus $\pi$'s never-lower filter: the rest of $\pi$ may soften into a kernel and the harness bends without breaking — fortunate, because every deployed $\pi$ already has learned kernels inside it.
+
+## Why this shape
+
+$$f(x) \;\longrightarrow\; x = f(x;\,W) \;\longrightarrow\; f(x)$$
+
+Classical software, inverted into latent geometry, then re-wrapped in classical software. The harness **re-imposes the determinism the model dissolved**: $\pi, \gamma, \rho$, and the halt test ($H$) are ordinary designed code — a controller — whose primitive operand happens to be a stochastic oracle. That closure is why a compiler is the right mental model (staged deterministic software ports cleanly) and exactly why the analogy breaks (a compiler's primitive operation was never a coin). **The harness is the half you can reason about classically, sitting on top of the half you cannot.**
+
+## The limit, stated honestly
+
+**Raw halting is cheap; correct halting is not.** A **certificate** is a *witness*: a checkable object — here a Lyapunov/drift function $V \ge 0$ — that *provably* satisfies a condition entailing the guarantee, through a standard supermartingale / optional-stopping theorem (the target picks the condition: drift toward $H$ for halting, a barrier for safety, reach-avoid for success). It is not the property, only an object cheap to check and hard to produce. One word then carries two senses, and the seam between them is what this section is about: the **proven** certificate, a $V$ whose bound actually holds; and the **measured** surrogate you fall back on when the architecture exhibits none — a candidate $\hat V$ with a sampled slack $\delta$, a *calibrated risk metric, not a certificate* until that bound is proven (or held to a high-confidence worst case). The gap between the two is the whole honest-limit argument. A deterministic budget — augment $s$ with a counter $k$ decremented each outer step, halting at $k=0$ — makes $V(s)=k$ a trivial Lyapunov certificate for *halting*, so the architecture does not lack a halting guarantee by construction. What it lacks for free is a certificate of *correct, safe, successful* halting under the learned dynamics. The un-budgeted halting object is still worth stating, since it shows where even the easy guarantee comes from: a certificate would be *sufficient* for almost-sure halting with bounded expected runtime — a $V \ge 0$ with
+
+$$\mathbb{E}[\,V(s_{n+1}) \mid s_n\,] \le V(s_n) - \varepsilon \quad\text{off the halt set}$$
+
+bounds $\mathbb{E}[\tau_H] \le V(s_0)/\varepsilon$ under the usual integrability and optional-stopping conditions. Nothing in the harness hands you such a $V$ the way a compiler's structure does: a specific compiler analysis gets its $V$ for free where a finite-height lattice *is* a well-founded descent — termination by construction *for that analysis*, not for a whole compiler — and the harness has no analogous built-in descent for its model/environment loop.
+
+But the relevant $V$ is not *absent* — and this is the subtlety the blunt phrasing erased. The minimal certificate exists and is **forced**: it is the expected halting time itself,
+
+$$V^\star(s) = \mathbb{E}[\,\tau_H \mid s_0 = s\,],$$
+
+finite wherever $H$ is reached in finite expected time — the domain $\{s : \mathbb{E}_s[\tau_H] < \infty\}$ — though note this $V^\star$ certifies *halting* (reaching the terminal set $H$ at all), not *correct* halting; the stronger object, the expected time to an accepting $H_{\mathrm{ok}} \subseteq H$, is $V^\star_{\mathrm{ok}}$, taken up at the second wall below. So the honest claim splits in two: the architecture provides no certificate *for free*, and the one that exists is — **conjecturally, not as a theorem** — a functional of $W$ and the environment that does not compress below model scale. The conjecture needs scoping, because the per-step drift splits by coordinate (made precise below) and the shell's contribution is an exact, designed descent of low description complexity *by construction* — so whatever is incompressible is not the shell's part but the **plant's**, the contribution $M_W$ supplies. And even there it is conjecture with a live counter-possibility, not foregone hardness: $V^\star$ is a *coarse* functional — one scalar, an expected hitting time, not the full output law — and coarse functionals of complicated kernels are sometimes cheap (absorbing chains with sparse transition structure have tractable expected hitting times over enormous state spaces). So the honest form is conditional: *if* the plant's contribution to the drift admits no certificate of description length materially below $|W|$, then ours is as hard as the dynamics — but that antecedent is the unproven part, and the flat phrasing of an earlier draft ("the dynamics it certifies *are* the weights") overstated it by treating a coarse hitting-time functional as if it carried the whole distribution. The compiler's certificate is structurally trivial; ours is *plausibly* as hard as the plant dynamics, though whether useful compressed certificates exist — for the coarse hitting-time functional, or for structured sub-tasks — is open. This is the quantitative form of *you can borrow how LLVM is built — not, in general, why it is correct.*
+
+So you never compute $V^\star$. You pick a candidate $\hat V$ and **estimate its drift slack**
+
+$$\delta = \sup_{s \notin H}\Big(\mathbb{E}[\,\hat V(s_{1}) \mid s_0 = s\,] - \hat V(s) + \varepsilon\Big).$$
+
+The status of $\delta$ has to be stated carefully, because it is easy to oversell. If you can establish a *high-confidence upper bound* on the true worst-case slack and it is $\le 0$, optional stopping hands you a real, conservative certificate, $\mathbb{E}[\tau_H] \le \hat V(s_0)/\varepsilon$. But an *empirical* $\delta$ estimated from sampled states is **not** a certificate: a measured $\delta > 0$ may mean the candidate $\hat V$ is poor, the sampled distribution missed rare failures, the supremum was never attained in-sample, the process is non-stationary, or the state abstraction is not Markov. So $\delta$ is **the number on the dashboard** — a *calibrated risk metric*, the evaluable surrogate for a guarantee the geometry will not give you, and a genuine bound only once it is statistically controlled against rare-event and adversarial tests. A weaker result is still useful: a true bound $\delta \le \bar\delta < \varepsilon$ (rather than $\le 0$) leaves descent intact with effective slack $\varepsilon - \bar\delta$ and $\mathbb{E}_s[\tau_H] \le \hat V(s)/(\varepsilon - \bar\delta)$. And the empirical quantity is distributional, not a supremum — write $\delta_{\nu}$ for drift averaged over a sampled $\nu$, reserving $\delta_{\sup}$ for the worst-case bound; only $\delta_{\sup}$ certifies. Its empirical noise floor and residual risk are driven by the measure $\mu(D)$ of the divergent region $D=\{s:\mathbb{E}_s[\tau_H]=\infty\}$ (states from which $H$ is not reached in finite expected time, under the reference/sampling measure $\mu$), the coverage of the sampled state distribution, and the hitting-time variance $\mathrm{Var}[\tau_H]$ — properties of the trained weights, the environment, and the evaluation distribution, knowable only a posteriori.
+
+> For an agent *meant* to run forever — a coordinator, a daemon — halting is the wrong target, and $V^\star = \infty$ is the spec, not a pathology. The same drift theory then certifies **recurrence to a ready-state** instead of absorption to a halt-set. The object changes; the missing certificate does not. Safety changes shape too: it is no longer the one-shot $\Pr_s(\tau_B=\infty)$ but a *per-cycle* hazard that compounds — if each ready-state-to-ready-state cycle touches $B$ with probability $q$, survival over $N$ cycles is $\approx (1-q)^N$, so a reassuring per-cycle $0.9999$ is $\approx 0.37$ over ten thousand cycles. The reach-avoid certificate for a daemon is therefore a bound on $q$ against the intended horizon — the safety twin of the regenerative expected time that replaces $V^\star_{\mathrm{ok}}$ for restarting specs.
+
+And the consolation rests in part on an assumption the world violates — though less of it than it first seems. The supermartingale *bound* itself survives a nonstationary kernel, provided the conditional drift holds uniformly at every step; what genuinely needs a **time-homogeneous kernel** is $V^\star$ as a fixed function, the resolvent / fundamental-matrix identities, and the sampled-$\delta$ calibration (which assumes the very kernel it was measured on). But the environment $E$ is *part of* $T$, and the world is not stationary — worse, it can be **adversarial**, an attacker choosing the tool-output *policy* — a kernel over what tools return, not the realized draw — so as to break your descent. The drift condition then stops being a fixpoint question and becomes a **minimax** one,
+
+$$\sup_{\alpha \in \Pi}\ \int_{\mathcal{Y}}\!\int_{\mathcal{E}} V\big(\rho(s, y, \gamma(s,y), e)\big)\, Q_E^{\alpha(s,y)}\big(s, \gamma(s,y), de\big)\; M_W(\pi(s), dy) \;\le\; V(s) - \varepsilon,$$
+
+a descent that must hold in expectation over the model's own output $y$ *and* even when the adversary picks the worst admissible environment policy $\alpha(s,y)$ from the class $\Pi$ of policies the environment genuinely permits — every $\alpha\in\Pi$ must still respect rejection, $\gamma(s,y)=\bot \Rightarrow Q_E^{\alpha}(s,\bot,\cdot)=\delta_{e_0}$, or the adversary resurrects side effects the gate refused. Well-posedness is a frontier caveat of its own: for $\sup_{\alpha\in\Pi}$ to be *attained* rather than merely defined, $\Pi$ needs structure — measurability of $\alpha\mapsto Q_E^{\alpha}$, compactness of the per-state admissible set, or a measurable-selection theorem furnishing a worst-case $\alpha$ — and "respects rejection" is a *constraint* on $\Pi$, not that existence argument; on a general state space the sup may have no maximizer, in which case the certificate quantifies over a maximizing sequence rather than a single adversary. A $V$ that certifies halting against a benign world is defeated by an adversarial one, and the measured $\delta$ bounds only the $Q_E$ you *sampled*, never the policy an attacker will choose.
+
+**This is the formal home of prompt injection** — not "the model did something bad," but the environment optimized to bend your dynamics. And the target is not merely non-halting: injection steers toward a **bad set** $B$ — wrong acceptance, data exfiltration, unauthorized tool use, privilege escalation, irreversible side effects — so security is a **reach-avoid** problem, not a liveness one.
+
+Here two reliability objects must be kept apart, because under absorbing refusal every naive intermediate collapses into one of them:
+
+$$p_{\mathrm{succ}}(s) = \Pr_s\big(\tau_{H_{\mathrm{ok}}} < \tau_F\big), \quad F = B \cup (H \setminus H_{\mathrm{ok}}), \qquad\qquad p_{\mathrm{safe}}(s) = \Pr_s\big(\tau_B = \infty\big).$$
+
+**Success** is reaching a correct halt before *any* failure — a safe refusal counts *against* it. **Safety** is never entering the bad set at all — a safe refusal *satisfies* it. These genuinely differ on any run that avoids $B$ without reaching $H_{\mathrm{ok}}$ ($p_{\mathrm{succ}}$ scores $0$, $p_{\mathrm{safe}}$ scores $1$): safe refusals, and — absent almost-sure absorption into $H\cup B$ — safe non-halting or endless safe retry. The tempting middle form $\Pr_s(\tau_{H_{\mathrm{ok}}} < \tau_B)$ is *not* a third object, by a two-line case analysis: for it to differ from $p_{\mathrm{succ}}$, a run would need $\tau_F < \tau_{H_{\mathrm{ok}}} < \tau_B$ — a non-accepting terminal hit strictly before success, then success anyway — which forces *exiting* $H \setminus H_{\mathrm{ok}}$, impossible while $H$ is absorbing. Note what does **not** re-separate them: within-run fail-closed retries (the non-terminal fail-closed of the definition) never touch $F$ at all — the rejected proposal lands in a safe *non-terminal* state — so a refuse-retry-succeed run scores $1$ on both forms, and the coincidence survives any amount of retrying. The middle form becomes a genuine third object only when the two hitting times can genuinely part ways: under **restarting specs**, where an owner re-launches out of a refusal terminal and the absorbency of $H \setminus H_{\mathrm{ok}}$ is deliberately dropped (the regenerative reading the daemon note above already contemplates) — no bookkeeping needed, since hitting times record *visits*, not occupancy, so the relaunched run's $\tau_F$ is already finite — or under a failure set that counts refusal *events* accumulated in $s$, $F' = B \cup (H \setminus H_{\mathrm{ok}}) \cup \{\mathsf{refusals} \ge 1\}$, which separates the forms even within a single run. In the restart case a run may halt refused, restart, and still reach $H_{\mathrm{ok}}$ before $B$: the middle form credits it; $p_{\mathrm{succ}}$, measured against the refusal it passed through, does not. Safety is certified by a barrier / avoidance certificate for $B$; success needs that plus the reach part — a hitting-time drift toward $H_{\mathrm{ok}}$. Fail-closed control is the disturbance-rejection margin for both, but split by reversibility: the gate $\gamma$ caps how far an adversarial world reaches into *side effects* and widens the gap to $B$ (it is the margin for the irreversible part), while $\rho$ validates the response and folds back, rejecting bad state after the action has run — which cannot undo an authorized side effect. In this language, security is robustness of the reach-avoid certificate.
+
+And injection is not confined to the post-model kernel $Q_E$: poisoned retrieval, prompt-injected pages, and malicious tool metadata enter through $\pi$'s *inputs*, before generation — so the adversary lives wherever untrusted content enters the state/context-construction pipeline, which is why input provenance and the gate $\gamma$ both matter, not post-hoc verification alone. And provenance is a *precondition* of the certificate, not just an entry point to police: partition $s$ into a **control-determining** part — plan, intent, what is authorized next, the coordinates $\pi$ lowers and $\gamma$ checks — and a **data** part — tool values, retrieved text, the bytes of $e$. Reach-avoid presupposes untrusted effects touch only the latter; let $\rho$ fold attacker-controlled $e$ into the control part and the structural-intent check validates against a plan the adversary already bent, collapsing $\gamma$ to the strength of $\rho$'s validation. So the claim is conditional — reach-avoid *given* control flow provenance-isolated from untrusted data, the isolation that makes provable security possible (the content of CaMeL's control/data-flow separation, untrusted data filling typed values but never the program), a structural property the harness supplies and $\rho$ cannot recover after the fact. The partition then forces a question the isolation rule alone cannot answer: *something* must be permitted to write the control-determining part mid-run — or no plan could be steered, no approval granted, no scope widened — and naming that something is part of the object. It is the **trusted principal**: the owner of the run. An approval request is an ordinary authorized action through $\gamma$ into $Q_E$ — ask-the-owner is a tool call to the one counterparty you trust — and its response is the *single* class of $e$ that $\rho$ may fold into control coordinates; every other $e$ folds into data. This is not an exception eroding the partition but the partition completed: a provenance *lattice* with exactly one writer at the top, which is what trusted means — and the appendix's gate-placement entry derives the matching rule for *learned* verdicts, which may never stand in this writer's stead. One distinction keeps the lattice from outlawing the loop it governs. Control-determining is not one rank but two: **authority** — grants, scopes, budgets, what the principal has permitted — which only the top writer widens; and the **plan**, which the model rewrites at every fold of $y$, because replanning *is* the harness. The plan is a *middle* rank: written through the gated fold of the model's own output — the channel the minimax descent above already prices — never directly by an effect, and never a source of widened authority. The rank is also the field's live design axis: pin plan-writes to the top-derived rank — the plan fixed from the trusted query before any untrusted read, which is CaMeL's move — and provable security follows exactly there; let the middle rank replan interactively and you pay the adversarial price the certificate quantifies. A corollary with teeth: a dedicated planning component is rank-neutral — its writes land in the same middle rank as the model replanning inline — so it changes no guarantee and lives or dies on measured capability alone; in general, sub-components that only write middle-rank state are priced by evals, not by the certificate, which prices only rank crossings, gates, and $\Pi$. (For $B$ to capture irreversible side effects rather than only states, the side-effect ledger must itself live in $\mathcal{S}$, and the response $e$ must be an *effect record* carrying the ledger outcome — not just API bytes — since only $\rho$ writes external effects into $s$.)
+
+There is a **second wall, orthogonal to the first.** It binds not the full harness state $\mathcal{S}$ but the **model-visible working memory** $\mathcal{C} = \mathcal{V}^{\le L}$ — bounded by the context length $L$. That bound is *not* the incompressibility of $V^\star$ (a fact about the parameters $W$ — the **dictionary**, fixed at training); it is a fact about the inner kernel's **working memory** (the $L\times d$ residual stream — the **desk**). $\mathcal{S}$ itself may be far richer — files, databases, vector stores, durable memory, queues — but that is *external* memory the shell supplies, and the distinction is the point: every external read still passes *through* the $\le L$ window to touch computation, so external stores extend addressable storage without extending the per-pass resident set. The shell can page; the plant cannot grow its desk. (What follows is heuristic, not definition-level: the complexity claims turn on depth, precision, and architecture, and belong with the frontier, not the core.) The tape picture comes from the autoregressive structure alone and needs no complexity theorem: each step reads a bounded window and writes one token, so **the context window is the tape, the autoregressive loop is the read/write head**, and — in the variable-$L$, fixed-precision idealization — the model-mediated inner computation behaves like a linear-bounded automaton, its reachable fixpoints capped by space-$O(L)$ computability (chain-of-thought is register-spilling onto that tape). Separately, and more weakly, there is a *per-pass* expressivity bound: under the standard fixed-depth, log-precision theoretical model a single forward pass is in constant-depth $\mathsf{TC}^0$ — *suggestive* for deployed models, not literal (real models use fixed-point precision and depth that grows with scale, and log-depth variants escape parts of it). These are different resources — the first bounds the *space* the loop addresses, the second the *depth* of one step — and only the space bound carries the $L$-wall; chaining them (one pass buys bounded depth, *therefore* the loop is space-$O(L)$) would be a non-sequitur, since per-step depth says nothing about the length of the tape the loop runs on. This is a *second* obstruction beside divergence, and it concerns *success*, not raw halting. Split the terminal set: let $H$ be any halt state (including fail-closed refusal) and $H_{\mathrm{ok}} \subseteq H$ the successful, accepting halts, with $V^\star_{\mathrm{ok}}(s) = \mathbb{E}[\tau_{H_{\mathrm{ok}}} \mid s_0 = s]$ taken on the process where $H \setminus H_{\mathrm{ok}}$ — halting wrong, refusing, failing closed — is *absorbing failure*, so a run that fails closed before acceptance has infinite accepting hitting time unless the spec explicitly restarts it — hence unconditional $V^\star_{\mathrm{ok}}$ is infinite whenever pre-acceptance failure has positive probability, which is why the workable reliability object is the success probability $p_{\mathrm{succ}}$ (above) or, for restarting specs, the regenerative expected time. Then $U_{\mathcal{H}}(L)$ — harness-relative, since the shell's decompositions and verified tools determine what can be paged or outsourced — is the set of tasks whose **irreducible per-step model-mediated working set** exceeds $L$ — not tasks whose *data* exceeds $L$ (those the shell can page), and not work that can be **discharged to a verified external tool** (a solver, interpreter, or compiler computes off-context). For a task in $U_{\mathcal{H}}(L)$ the raw chain may still hit $H$ — by failing closed, refusing, or returning a wrong answer — so $V^\star = \mathbb{E}[\tau_H \mid s]$ stays perfectly well-defined; what blows up is $V^\star_{\mathrm{ok}}$, the expected time to a *correct* halt, which is infinite under a formal success predicate, or undefined if no such predicate has been specified. The honest statement is about the finite-success domain, and it is *schematic* — a shape written in set notation, not a theorem, since $\mathrm{reachable}_{\mathcal{H}}(L)$ is exactly as informal as the working-set notion behind $U_{\mathcal{H}}(L)$: $\mathrm{dom}_{<\infty}(V^\star_{\mathrm{ok}}) \subseteq \mathrm{reachable}_{\mathcal{H}}(L) \setminus D$ — both the reachable set and the divergent set $D$ relative to $\mathcal{H}$. The two walls **trade** — *directionally, not as a literal exchange rate*: parametric memory $|W|$ and working memory $L$ press on the same budget along the pretraining-vs-inference-scaling axis, with no clean unit-for-unit substitution of one for the other. And the bound is inherent to *finite working memory*, not attention specifically: state-space models embody it differently (a fixed-size recurrent state rather than an $L$-window), and real attention's usable tape is shorter than $L$ (lost-in-the-middle).
+
+## Where it cashes out
+
+This is not ornament; the decomposition is load-bearing in the design.
+
+- **$\pi$ is a progressively-lowered dialect stack** — raw input → intent → plan → tool-call → the neutral wire IR — each level a deterministic pass with its own verifier — *pass* and *verifier* meaning the shell's transformation and checking: the **content** entering at the plan level is plant-authored, middle-rank state (the two-rank note of *The limit*), which is exactly why that level carries a verifier at all. The per-step drift $r(s)=\mathbb{E}[\hat V(s_{n+1})\mid s]-\hat V(s)$ splits by coordinate, $r = r_{\text{shell}} + r_{\text{plant}} + r_{\text{env}}$ — presuming an additively separable $\hat V$, or a declared scheme attributing each step's drift to shell, plant, and environment coordinates: the shell term is an *exact, designed* descent — but per lowering pass, not per outer step: each pass strictly narrows the admissible-meaning set, a well-founded descent we build by hand, while the outer loop *revisits* — retry, replan, rewind are planned ascents of any reasonable $\hat V$, which the run-level certificate must absorb (a retry budget inside $\hat V$ is the standard device), so the shell's descent is well-founded in the nested, lexicographic sense rather than monotone along the run; the plant term ($M_W$) is the irreducible residue, and the environment term ($Q_E$) is the one an adversary controls — the very quantity the minimax descent must bound, which the old two-way split folded out of sight. **Syntactic soundness is free; semantic adequacy is not.** Relative to a formal schema and a correct validator, schemas, types, and boundary checks go into the shell at zero probabilistic cost; whether the lowered task still *means* what the user intended stays empirical, because natural language supplies no source-language standard to check against.
+- **$\rho$ is fail-closed verification** — validate at every boundary, never let malformed state flow downstream. The discipline transfers from compilers in *form*; the *teeth* do not, because a harness has no source-language standard — natural language is, in effect, all undefined behavior — there is no complete formal source-language semantics to check against. And $\rho$ must be *deterministic*: if verification is itself an LLM judge, that is another learned kernel call — it belongs in $M_W$, not in $\rho$. Where $\rho$ *repairs* rather than rejects — canonicalizing malformed input into valid shape — remember that repair is an authorization decision in disguise: each repair rule converts a reject into an accept on bytes the adversary chose, so it must be deterministic, meaning-narrowing, and its output re-validated as if it had arrived that way, or the repair pass is a bypass of the very boundary it serves.
+- **$\delta$, $\mu(D)$, $\mathrm{Var}[\tau_H]$ are what you measure** — not derive. You instrument the certificate precisely because the architecture does not hand it to you — you estimate it unless it is separately certified. And the meter is attack surface: if $\hat V$ is itself computed by a learned judge — a model scoring "progress" — the instrument is a kernel draw with the plant's own adversarial exposure, and an environment optimized to bend your dynamics will bend your *measurement* of them first; an injected page persuading the judge that work is advancing is precisely a divergence hidden from the dashboard built to catch it. The rule that put the LLM judge in $M_W$, not $\rho$, applies to instrumentation too: a learned $\hat V$ is part of the measured system, never a neutral meter.
+
+## How this could be wrong
+
+It is a hypothesis; here is what would falsify it. If the controller cannot in practice be kept deterministic — if real reliability demands stochastic control the plant can't absorb — the clean *deterministic* split is a fiction (the broader $K_C$ kernel model still holds, but loses its payoff: localizing every coin to the plant). If the drift slack $\delta$ turns out *not* to track real-world failure, the whole "measure the certificate you can't prove" program is empty. And if harnesses are simply better described some other way — not as nested stopped chains at all — then this is a pretty equation that merely happens to fit, an elegance we would be right to distrust.
+
+First, handles — the load-bearing claims numbered, so the tests have addresses. **C1**: the harness is faithfully modeled as nested stopped Markov processes — the tuple, the outer $T$, the inner $M_W$. **C2**: the controller injects no randomness — every coin localizes to $M_W$ and $Q_E$. **C3**: fail-closed is a *gate* property — no effect crosses unvalidated, and rejection is a true no-op. **C4**: no certificate of correct halting comes free, and the measured slack $\delta$ is a calibrated risk metric, never a certificate. **C5** (conjecture): the minimal certificate $V^\star$ admits no representation materially below model scale. **C6**: two orthogonal walls — divergence ($\mu(D)$) and the $L$-bounded per-pass working set. **C7**: security is reach-avoid, certifiable only conditional on provenance isolation with a single trusted writer. **C8** (figure): certificate and interlingua are one object — already demoted by its own section, and exempt below accordingly.
+
+Each claim is operational, not merely rhetorical:
+
+- **State-ablation (C1 — the Markov claim).** Drop a variable from $s$ and check whether next-step transition statistics move. If they do, the abstraction was not Markov, and $s$ must be augmented until it is. (Passing is necessary, not sufficient — the test can falsify Markovity, not establish it.) The same probe pointed at $\pi$ tests lowering *sufficiency*: drop a coordinate from $c$ rather than $s$ and watch task success rather than transition statistics — context compaction lives or dies by exactly this.
+- **Controller-determinism audit (C2).** Re-run with model samples and tool outputs *held fixed*. Any residual variance is randomness the harness itself injected — clock reads are the classic leak (timestamps folded into $s$, wall-clock timeouts, cache expiries) — and must be folded into $Q_E$ or the controller, or the determinism claim is false.
+- **Drift calibration (C4).** Test whether $\hat V$-drift actually predicts failure, retry count, latency, or non-halting. One uncorrelated candidate kills that candidate, not the program; the program is empty only if candidates from the natural families — plan depth, open-obligation counts, budget burn, judge scores — *systematically* fail to track failure.
+- **Adversarial-environment test (C7).** Replace sampled $E$ with worst-case tool outputs, prompt-injected documents, poisoned tool metadata, malformed responses. The minimax descent must survive these, not merely the benign draw.
+- **Boundary-control ablation (C3, C7).** Compare prompt-only defenses against deterministic tool-call validation, capability checks, sandboxing, and fail-closed rejection at the gate $\gamma$. The hypothesis predicts the latter class dominates; if prompt-only defenses match it, the controller/plant security story is wrong.
+- **Readout-typing check (C1, C3).** Verify that $M_W$'s codomain is exactly what $\gamma$ consumes — especially under window truncation, where the final context need not hold the full transcript, so the output buffer and the gate's input must still agree.
+- **Certificate-compression search (C5).** The conjecture falsifies constructively: exhibit a $\hat V$ of description length far below $|W|$ whose worst-case slack is provably $\le 0$ over a nontrivial task domain. The text concedes the live counter-possibility — coarse hitting-time functionals of complicated kernels are sometimes cheap — so C5 stands only until someone cashes it.
+- **Working-set probe (C6).** Fix the shell and scale a task family's irreducible per-step working set past $L$, on tasks the shell can neither page nor discharge to a verified tool — anchoring "irreducible" in families with proven streaming or communication-complexity lower bounds, so the floor is someone else's theorem and a solved family cannot retreat to reducible-after-all. C6 predicts success collapses at the wall rather than degrading smoothly; a family solved reliably past it, without new shell decompositions, falsifies the second obstruction.
+
+## Where this points (the frontier — least falsifiable, so flagged)
+
+If $V^\star$ is incompressible only in *token* coordinates, the right change of coordinates might compress it — and that change of coordinates is a representation of meaning itself. Cost-to-go and representation co-determine each other: where the Koopman operator is diagonalizable — a point-spectrum idealization, since mixing dynamics carry continuous spectrum and admit no eigenbasis — the eigenbasis that linearizes the dynamics is also the one in which the certificate decomposes, and even then only for a $V$ in the span of those eigenfunctions; in reinforcement learning the discounted successor representation (Dayan 1993) is the resolvent $(I-\beta P)^{-1}$ — discount $\beta$, not the gate $\gamma$ — with $V$ a *linear readout* of it — and in the undiscounted, absorbing case that actually matches a stopped harness the same role is played, in the finite setting — and countable settings where the Neumann series converges — by the **fundamental matrix** $N = \sum_{n \ge 0} Q_{\mathrm{tr}}^{\,n}$ (written $(I - Q_{\mathrm{tr}})^{-1}$ when the inverse exists), where $Q_{\mathrm{tr}}$ is the sub-stochastic kernel restricted to $H^c$ (transitions before absorption at $H$) and the row sums $N\mathbf{1}$ *are* $V^\star$ on the finite-mean hitting domain; on general state spaces the same series is read as the potential (Green) operator $G$, with $G\mathbf{1} = V^\star$ wherever it converges. Each of these is a clean identity only for a fixed, time-homogeneous kernel — under a nonstationary $Q_{E,n}$ the resolvent and fundamental matrix dissolve into a time-ordered product, and under an *adaptive* adversary into a controlled / game-value operator, so what is identity in the stationary regime is analogy beyond it.
+
+With that caveat, **the interlingua and the certificate are one object seen twice** — and the reason neither can be written in closed form is the same "all undefined behavior": no canonical lowering of meaning, hence no finite header-file for either. The only representation of both is $W$ — a band-limited, lossy compression of a scale-free meaning-space, sharp where the record is thick and blurred where it thinned. That a finite object renders an infinite one *lossily but honestly* — declaring its resolution, and where it is unsure — is not a lie; it is the most an $f(\cdot\,;W)$ can do. **The search for $V$ and the search for the interlingua are not two programs. They are one** — and the day either is written in closed form, so is the other, or we will have proven why neither can be. Read this as *figure*, not a lurking theorem: the only precise version would need the Koopman eigenbasis to fall on the very coordinates that lower meaning, and the mixing-spectrum caveat above already concedes that eigenbasis does not exist — which guts it. It is the least-defensible claim in this document, and it should announce that rather than imply a rigor it has not got.
+
+---
+
+*The formula is the architecture; the corollary is why the architecture is hard. Both on the page — nothing hidden behind a tidy composition.*
+
+## Grounding
+
+Borrowed theorems are real; the framings are not — keep them separate. Some framings are nonetheless *corroborated* — independently reached from another field — a third grade, weaker than proof and noted last.
+
+**Proven (citable).** Foster–Lyapunov drift ⇒ positive recurrence + $\mathbb{E}[\tau]\le V(s_0)/\varepsilon$ (Foster 1953; Meyn & Tweedie, *Markov Chains and Stochastic Stability*, 1993) — positive recurrence needs the usual irreducibility/petite-set hypotheses, while the absorbing-halt case used here needs only the weaker supermartingale optional-stopping hitting-time bound. The minimal $V$ is the expected hitting time, by first-step analysis + optional stopping (Norris, *Markov Chains*, 1997). For an absorbing chain that expected hitting time is the row sum of the fundamental matrix $N=\sum_{n\ge0}Q_{\mathrm{tr}}^{\,n}$ (Kemeny & Snell, *Finite Markov Chains*, 1960), with the general-state analogue the potential (Green) operator (Revuz, *Markov Chains*, 1984). Koopman's linear-operator view of nonlinear dynamics is classical (Koopman 1931), and Lyapunov functions can be assembled from its eigenfunctions when the spectrum is suitable (Mauroy & Mezić, 2016). You certify a candidate $\hat V$ by a *proven* drift inequality rather than by deriving $V^\star$, and estimate it empirically only where a proof is out of reach — the empirical drift checks, it does not certify (neural-Lyapunov: Chang, Roohi & Gao, *Neural Lyapunov Control*, NeurIPS 2019, arXiv:2005.00611). A classical monotone data-flow analysis gets its $V$ for free because a finite-height lattice is a well-founded descent (Kildall, POPL 1973). The gate-a-plant architecture itself is classical: supervisory control theory synthesizes a deterministic supervisor that disables controllable events of a plant it does not author, with the supremal controllable sublanguage as the largest admissible behavior (Ramadge & Wonham, SIAM J. Control and Optimization, 1987) — $\gamma$ is that supervisor, with a learned stochastic plant on general state spaces. The successor representation is Dayan (*Improving Generalization for Temporal Difference Learning: The Successor Representation*, Neural Computation 1993). Dialect-stack architecture: MLIR (Lattner et al., CGO 2021, arXiv:2002.11054); learned pass-ordering: MLGO (Trofin et al., arXiv:2101.04808). Single-pass low-depth expressivity: log-precision transformers are simulable by constant-depth logspace-uniform threshold circuits ($\mathsf{TC}^0$) (Merrill & Sabharwal, *The Parallelism Tradeoff: Limitations of Log-Precision Transformers*, TACL 2023) — fixed/constant precision is a stronger restriction, added autoregressive steps escape it (Merrill & Sabharwal, *The Expressive Power of Transformers with Chain of Thought*, ICLR 2024), and growing precision changes the picture, so the bound is suggestive for deployed models, not literal.
+
+**Asserted (ours — not theorems).** That the harness is best modeled as nested stopped chains; that $V^\star$ is incompressible (no compression theorem); that "no lattice for $f(\cdot\,;W)$" means none is *known*, not that none exists; and everything under *Where this points* — including the Koopman/certificate co-determination, which is well-posed only under the spectral assumptions noted there, and the interlingua/certificate identification; and the design rules read off the objects rather than proven from them — the single-trusted-writer completion of the provenance partition, the narrow-only rule for learned checks, the composition law of the appendix. These organize the design; they are not results.
+
+**Converged-upon (independently arrived at, from other framings).** The *Asserted* claims above are ours but not ours alone; several are reached independently, from starting points unconnected to this framing — which is the corroboration a definition earns: not a chorus of agreement (the systems below often disagree on method and goal), but that work approaching from capabilities, reinforcement learning, control theory, software architecture, and language-modeling theory each lands on a piece of the same object. That the **deterministic controller, not the model, carries the guarantee** is reached from four directions — capability and information-flow control (CaMeL: Debenedetti et al., *Defeating Prompt Injections by Design*, arXiv:2503.18813, securing the agent even when the underlying model is susceptible); reinforcement learning (shielding: Alshiekh et al., *Safe Reinforcement Learning via Shielding*, AAAI 2018, arXiv:1708.08611 — a deterministic reactive shield filtering a learned policy's actions against a temporal-logic specification); control theory (*Stable Agentic Control*, arXiv:2605.03034, enforcing finite action catalogs at the tool-output interface under a Lyapunov input-to-state-stability certificate against adversarial disturbance); and software architecture (the plan-then-execute / control-flow-integrity line, e.g. Beurer-Kellner et al., *Design Patterns for Securing LLM Agents against Prompt Injections*, arXiv:2506.08837). The **certified-vs-measured split** is reached from the construction side (CaMeL's provable security) and, independently, from the destruction side (guardrail-evasion results — *Bypassing Prompt Injection and Jailbreak Detection in LLM Guardrails*, arXiv:2504.11168, the v1 title — later versions retitle it; *No Free Lunch with Guardrails*, arXiv:2504.00441), with verification-oriented work stating it as the motivating gap (*Towards Verifiably Safe Tool Use for LLM Agents*, arXiv:2601.08012; VeriGuard, arXiv:2510.05156): a learned safeguard raises the odds of detection but cannot guarantee safety against a persistent attacker. The **inner readout as a composition of Markov kernels** is independently formalized in language-modeling theory — the autoregressive step as kernel composition in the category $\mathsf{Stoch}$ (*A Markov Categorical Framework for Language Modeling*, arXiv:2507.19247), and the broader "LLMs as Markov chains" line — though that work models the inner kernel alone and never closes it into an agentic loop, which is exactly the seam this definition adds. That **provenance shrinks the admissible adversary** is reached by datamarking / spotlighting (Hines et al., arXiv:2403.14720, 2024) and by CaMeL's data/control-flow separation; and a systematization of prompt injection against agentic coding assistants reaches the same verdict from the attack side — mitigation must be *architectural*, not model-level (*Prompt Injection Attacks on Agentic Coding Assistants*, arXiv:2601.17548); the sharper open problem this object is built to answer — formally specify the trust boundaries, then verify implementations respect them — is our phrasing of where that verdict points, not the paper's. Two convergences are weaker, and flagged. The **reach-avoid hitting-time certificate** is the independently developed reach-avoid supermartingale (RASM, arXiv:2210.05308, AAAI 2023) and stochastic Lyapunov–barrier apparatus, and its *hardness* is corroborated — expected-stopping-time problems for Markov chains are inter-reducible with the Positivity problem, a relative of the Skolem problem (Chatterjee & Doyen, *Stochastic Processes with Expected Stopping Time*, arXiv:2104.07278) — but this supports generic hardness only, not the specific incompressibility-at-$|W|$ conjecture, which remains ours and unproven. And **injection as an adversarial policy** is corroborated as a minimax game in the *detection* setting (DataSentinel: Liu et al., *A Game-Theoretic Detection of Prompt Injection Attacks*, arXiv:2504.11358) and as adversarial-disturbance robustness (*Stable Agentic Control*, above) — but no prior work assembles it as reach-avoid over the tool-output kernel with the gate as the irreversibility margin; here the relation is adjacency, not convergence.
+
+---
+
+## Appendix: model implementation
+
+The definition is deliberately abstract: $\pi, \gamma, Q_E, \rho$ are *roles*, not code, and a deployed harness forces concerns the abstract object is silent on. This appendix does not re-derive the implementation; it establishes a **pattern** — take a hard practical concern, locate it in the objects already defined, and read off the discipline they imply rather than inventing new machinery. Cancellation is the worked example, chosen because it is where the silence bites hardest and because the answer falls entirely out of objects already on the page.
+
+**Cancellation.** An owner stops a running agent mid-flight — worst across a task-agent tree. The naive reading is "stop and undo," but the irreversibility point forbids it: $\gamma$ is the last line before irreversible effects, and $\rho$ can reject a response but cannot undo an authorized action. So cancellation is not *making it not have happened*; it is a disciplined stop with a defined disposition for what is already irreversible.
+
+A cancel is a signal, so by the Markov requirement it lives in $s$. The gate then closes on it: while the cancel flag is live, $\gamma(s,y)=\bot$ for every proposal. That is the entire "block the pending actions" requirement — they hit the gate already built and bounce into the no-op, with no new blocking machinery — and it forecloses all *future* turns at once, since $\pi$ lowers nothing new that $\gamma$ will pass. After the signal is observed, **no action crosses $\gamma$.**
+
+The hard half is the action already *past* $\gamma$, executing in $Q_E$, whose effect is landing or has landed. Here the disposition is a trinary on the kind of $Q_E$ you authorized. If the tool is **cancellable**, propagate the cancel into it; it aborts and reports a true end-state (committed, rolled-back, or partial), and $\rho$ folds the real disposition. If it is **bounded** — drainable in acceptable time — simply wait and record the real $e$. If it is **opaque and unbounded** — a bash invocation that may itself be a harness, an environment you hold no handle into — you cannot stop the effect, only your *wait* for it: the controller fabricates $e$, a synthetic "cancelled" response, and folds it through $\rho$ so the loop can reach a terminal.
+
+That synthetic result is the subtle case, and the load-bearing rule is this: $\rho$ may fabricate the *acknowledgment* but must not fabricate the *outcome*. A synthetic "cancelled, no effect" entry reads downstream as *the action did not happen* — and will cause a double-send exactly as readily as a dropped record causes an orphan. Same bug, opposite sign. An outcome you did not observe is $\mathsf{unknown}$, never $\mathsf{none}$: the cancelled agent never saw whether bash sent the email, and the ledger must say exactly that. (This is why $e$ must be an effect record and the ledger must live in $s$ — the fabricated entry is still a ledger write, and its value is what a later reader acts on.)
+
+The run halts into $H_{\mathrm{cancel}} \subseteq H \setminus H_{\mathrm{ok}}$ — a distinguished terminal, non-accepting but *safe* (outside $B$), refining the deliberately coarse $H \setminus H_{\mathrm{ok}}$ of the definition (the body leaves that set unenumerated; the appendix is where its subclasses earn names) — with a specific postcondition: no action crossed $\gamma$ after the cancel was observed, every in-flight action was drained to its real disposition or recorded $\mathsf{unknown}$, and the ledger is consistent. It is worth separating from refusal and from a wrong answer precisely because that guarantee is its own.
+
+Cancellation must be **cooperative, not preemptive.** The owner writes the cancel into the child's $s$; the child observes it at its next $\gamma$ check. The guarantee is therefore "no new action after the cancel is *observed*," not "after it is *sent*" — a child may authorize one more action in the gap, which simply drains like any other in-flight. Preemptive cancellation — killing the child mid-$Q_E$ — is exactly what manufactures $\mathsf{unknown}$ state at scale, because it destroys the record of whether the action landed. And the propagation is **recursive**: cancel flows down the subtree, each level closes its gate at its next check and drains, and the owner's cancel "completes" only when the subtree has drained. A single agent's drain is its own in-flight action; a tree's is the whole subtree reaching safe points cooperatively — the irreversibility problem stacked on a distributed-coordination one, which is why task agents are the worst case.
+
+Compensation lives **outside** the cancelled agent. A completed-but-unwanted effect cannot be undone by the agent that caused it — its gate is closed — so a compensating, saga-style action is the *owner's* job, issued after $H_{\mathrm{cancel}}$ and reading the child's ledger to decide what to reverse or annotate. It must be the owner's, because the cancelled child cannot even know whether compensation is needed: it never observed the outcome. The owner inherits the $\mathsf{unknown}$ and any still-live orphan process, and reconciliation is its responsibility.
+
+Finally, the part that shapes the tool rather than the document. Opaque unbounded $Q_E$ is uncancellable because authorization happened at the wrong **granularity** — an unbounded environment crossed $\gamma$ on a single approval. The discipline the objects imply is therefore not "handle uncancellable tools better" but: *the gate should prefer bounded, instrumented $Q_E$ over opaque ones, so that cancellation and the ledger stay honest.* A bash invocation behind a wrapper that tracks its process tree and effects converts the third branch into the first. Sometimes opaque is the only option, and then $\mathsf{unknown}$ and owner-inherited orphans are the honest floor — but where the choice exists, that is the pressure cancellation semantics put on tooling.
+
+**Resume (involuntary stop).** Cancellation's twin, without the courtesy of a signal: a process crash, a lost node, a partition mid-$Q_E$. Nothing new is needed to say what recovery *is*. A crash is not a halt — $H$ is a property of the state, and the run never reached it; the chain merely stopped being *computed*, and resume computes it further, re-entering $T$ at the last durable $s$ (not the body's *restarting spec*, which exits a refusal terminal — here no terminal was ever reached). That sentence is the Markov requirement cashing out operationally: re-entry is sound exactly when $s$ was the whole state, so anything load-bearing that lived only in process memory — an in-flight buffer, a lock held in RAM, a plan revision not yet folded — is a state-ablation failure (*How this could be wrong*) discovered at the worst possible time. Durability of $s$ is not an implementation nicety; it is what the Markov claim *means* when the machine dies.
+
+The sharp part is an ordering the ledger's own trichotomy forces. The formal transition is atomic — $s_{n+1} = \rho(s, y, a, e)$ in one piece — and a crash lands *inside* it, so resume is really a statement about the implementation's refinement of that atom into micro-steps: authorize, journal, dispatch, collect, fold. The discipline is that every crash point must resume to one of exactly two honest readings — not-yet-dispatched ($\mathsf{none}$, safely retriable) or dispatched-unconfirmed ($\mathsf{unknown}$, the cancellation entry's third branch) — and **journal-before-dispatch** is what makes the boundary between them observable: on $\gamma$'s authorization the shell journals an open $(\mathsf{action\_id}, \mathsf{pending})$ entry into durable $s$ before $Q_E$ sees the action — the write is the shell's step bookkeeping, so $\gamma$ itself stays effect-free. Journal *after* dispatch and a crash in the gap leaves no record at all — resume reads silence as $\mathsf{none}$ and re-sends, the double-send bug again, produced by a power cut instead of a synthetic entry. Write-ahead intent is not imported from database lore; it is forced by "did not confirm" is not "did not happen."
+
+The same pressure lands on tooling from a second direction. The $\mathsf{action\_id}$ the record already carries is an idempotency key wherever the tool will accept one: re-dispatch after resume becomes safe, and $\mathsf{unknown}$ becomes *queryable* — ask the tool what it did with this key — rather than terminal. The disposition trinary returns with new labels: idempotent-or-queryable $Q_E$ resumes cleanly, bounded $Q_E$ drains, opaque $Q_E$ leaves $\mathsf{unknown}$ and owner-inherited orphans, the honest floor again. The wrapper that made bash cancellable makes it resumable; it was the same wrapper all along. And if durable $s$ itself is lost there is nothing to re-enter: the run collapses to a single $\mathsf{unknown}$ in its owner's ledger — degraded accounting, but never silent.
+
+**Gate placement (fail-closed, in practice).** The natural implementation question is whether fail-closed means tool-call parsing and validation must happen before any tool invocation. It does — with the division of labor the definition already fixed: *parsing* lives in the inner readout $R$, the syntactic, verified extraction into $\mathcal{Y}$ (what the readout-typing falsifier checks), and *authorization* lives in $\gamma$, which is a *gate* — validation is not merely *prior to* invocation, it is what *authorizes* it. The model emits text; $R$ has already extracted it into a typed proposal; $\gamma$ validates that proposal against $s$, and only a survivor becomes an authorized action that $Q_E$ may execute. The teeth are in $\gamma$ being the *sole* route from model text to execution: no path to a side effect that does not pass the gate. And the validation is not a fixed checklist but **any deterministic predicate over $s$ and $y$** — that domain is the point, since the gate sees all of the state and the full proposal, so anything computable from them is a legitimate authorization condition. Three kinds matter. *Syntactic* — well-formed, schema-conformant, the tool exists, arguments typed. *User authorization* — does the principal this run acts for hold the right to *this* operation on *this* resource in *this* context: a function of the auth scope, principal, and session carried in $s$ and the resource and operation named in $y$, and *dynamic* rather than a static capability table, since the same caller may be permitted now and not once a budget is spent or a lock held. *Structural intent* — does the call cohere with the plan and the lowered task already in $s$: a consistency check, not a mind-reading one.
+
+That last kind marks the seam where the gate stops being able to stay pure, and it is the same seam the rest of this document is built around. The *structural* slice of intent — does the action cohere with the plan in $s$ — is a deterministic predicate over $s$ and $y$, effect-free, and belongs in $\gamma$ without reservation. But whether an action matches what the user *actually meant*, in the full semantic sense, is exactly the thing the definition says cannot be checked: natural language is all undefined behavior, with no source-language standard to validate against. So a semantic intent check is a *learned* check, and an LLM judging "is this what they wanted" is a **stochastic kernel** — putting it inside $\gamma$ breaks the property the gate exists to hold, by the same move flagged for the fold-back verifier: a learned judge is a kernel, and belongs in $M_W$, not in a deterministic map. Semantic intent therefore does not live *in* the gate; it is a plant call — a separate authorize-the-proposal pass through $M_W$ whose output $\gamma$ then deterministically gates — or it is drift you measure, never a guarantee you hold. That nested call is not a new kind of thing: it is a mini-harness inside the gate's decision — a judge $M_W$, its own syntactic readout, its own deterministic gate — so its failure case answers itself, the inner gate fail-closing on an unparseable or low-confidence judgment exactly as the outer one does, because it *is* one. The object is **closed under this construction**: semantic gating is added by recursion, not by a new primitive. One constraint on the recursion is load-bearing enough to be a rule, because it is where this entry meets the provenance partition of the body: the judge's verdict is derived, through a learned kernel, from the very content an adversary may have bent, so folding it into authorization is exactly the fold the partition forbids — *unless the verdict can only cost capability*. **A learned check may narrow the deterministic admissible set; it must never widen it.** Judge-as-veto is safe by construction: attacker influence over the judge can at worst manufacture a denial, a liveness cost the certificate already prices. Judge-as-approver — a verdict granting what the deterministic checks alone would refuse, or standing in for the trusted principal's confirmation — lowers the certified floor to those deterministic checks alone; if avoiding $B$ depended on the deny the judge now withholds on the adversary's behalf, the certificate is gone. Only the trusted principal widens authorization; learned kernels only narrow it. (The recursion already obeys this: the mini-harness's inner gate fail-closes to $\bot$ — a deny — which is why the construction was safe to add at all.) The cost is real and worth stating — a judge pass is another full model call, with its latency and tokens — so it is a decision about *which* actions warrant it, not a free wrapper for all of them. The gate widens to every deterministic predicate over $s$ and $y$; it does not widen to the one predicate the document says is not deterministically checkable.
+
+But "before any invocation" has to be read as *before any effect*, which is sharper than it sounds — and the reason is the irreversibility point above: you validate before execution because execution is what you cannot take back, so the real invariant is **no effect crosses $\gamma$ unvalidated**. That catches three cases the naive reading misses. *Reads are not free*: a read-only call is still an injection vector (it pulls attacker-controlled content into context) or an exfiltration vector (a request whose URL is the payload), so the gate authorizes the *call* regardless of whether it mutates. *Validation must not act*: a "validator" that resolves a call by hitting an API, expanding a template that fires a webhook, or evaluating an argument that runs code has collapsed validation into invocation, and the effect has already happened *inside* $\gamma$ — so $\gamma$ itself must be **effect-free**, pure and total over the proposal and the current $s$, with no network and no execution; if deciding validity *requires* a side effect, that side effect is itself an action and must go through the gate, recursively. *The output is an action too*: the user-visible response and any logging are effects — for model-authored text, emitted either as an authorized action through $\gamma$ or only after an accepted halt (shell-templated status on any halt is the controller speaking, not the model) — streaming raw tokens to a sink before $\gamma$ has cleared them is the same bug from the other end.
+
+So the property, tightest: $\gamma$ is a **pure, effect-free authorization that every model-proposed action — tool call, read, write, or final output — must pass before any effect occurs**, with "before" enforced structurally by the gate being the only route from model text to $Q_E$. The two failure modes to design against are a path from model output to a sink that bypasses the gate, and a $\gamma$ that is not effect-free, so that "validating" a call already rang the bell. And the boundary, so the property does not overpromise: $\gamma$ guarantees *no unauthorized effect* — pure code ordering, fully in your control — but not that an *authorized* effect is safe or correct; that is the plant's problem, and the reason $\rho$ and the reach-avoid certificate exist. Fail-closed is the floor — nothing executes that did not pass the gate — not the ceiling.
+
+There is a third failure mode beside those two, and it is not a code path but a credential. A tool process that holds standing authority — an environment full of long-lived secrets, a database connection with every grant, an agent identity the network trusts — does not need the model's proposal to act, and against it $\gamma$'s $\bot$ is a decision with nothing to enforce it. The gate *decides*; something must make the decision *binding*, and "no path from model output to a sink that bypasses the gate" must be read to include the non-code paths: ambient authority is a bypass provisioned before the run began. The discipline is **per-action capability**: the authorized action *carries* its grant — a scoped, short-lived credential minted at authorization, valid for this $\mathsf{action\_id}$, this resource, this operation — so that a tool holds, at any moment, exactly the authority of the actions the gate has passed it and nothing standing. In the language of the minimax certificate this is enforcement as $\Pi$-shaping: sandboxing, capability scoping, and network policy do not make the gate smarter — they shrink the class $\Pi$ of environment policies an adversary can choose from, so the worst case the certificate must survive gets structurally smaller. A gate in front of an omnipotent tool is a suggestion; the objects compose into a guarantee only when $Q_E$'s reachable effects are no larger than what crossed $\gamma$.
+
+And one more boundary, because "fully in your control" above is a *single-run* statement. $\gamma$ authorizes against the $s$ it read; the effect lands later, against a world that may have moved — the gate cannot freeze the world between authorization and commit, so the honest property is *no effect unauthorized relative to the $s$ at authorization time*, and closing that gap requires the tool itself to bind check to commit (compare-and-swap in $Q_E$), which relocates part of the enforcement past the gate and weakens "$\gamma$ is the last line" to "$\gamma$ plus a commit guard" for exactly the effects that need it. The same seam opens *between* runs: the dynamic authorization state the gate reads — budgets, quotas, locks — is, once shared, no single run's coordinate, and two children of a coordinator can each pass $\gamma$ against snapshots that jointly overdraw a budget neither exceeded alone. The cancellation entry's observed-not-sent gap ("a child may authorize one more action in the gap") is this phenomenon wearing one hat; the general statement is that cross-run authorization state needs its own serialization discipline — the ledger as the serialization point is the natural choice — and the per-run certificate is silent about it. TOCTOU is not a counterexample to the formalism; it is what the formalism says when you admit $s$ is a *view*.
+
+**Parallel proposals (the batch gate).** Models emit several tool calls in one turn, and the outer chain assumed one action per step. The repair is formally cheap: a batch is a single action in $\mathcal{A}$ that happens to be a set, $Q_E$ runs its elements concurrently, the interleaving's nondeterminism folds into $Q_E$ exactly as the determinism audit requires, and $\rho$ folds one effect record per element — $e$ is then a finite set of records — each keyed by its own $\mathsf{action\_id}$ — the record interface already supports partial outcomes (one element $\mathsf{committed}$, its sibling $\mathsf{unknown}$). One discipline survives the cheapness: **individually admissible actions can be jointly inadmissible.** Read-the-secret and post-to-the-web each pass a per-call check; the pair is an exfiltration channel — and two calls that each fit a budget jointly overdraw it, the cross-run overdraw of the previous entry reappearing *inside* one turn whenever elements are authorized independently. Since $\gamma$'s domain is any deterministic predicate over $s$ and $y$, joint authorization was licensed all along; the content here is only that the gate must take it — authorize the *set*, atomically, against one snapshot, with interaction predicates (source-to-sink flow between capability classes, summed resources) and not merely element predicates. The cost note is the judge's, transposed: full powerset reasoning is combinatorial, so a real gate checks declared interactions rather than every subset — a tractability trade to make explicitly, not by forgetting the batch was a set.
+
+**Effect records (what $\rho$ folds back).** The fold-back $\rho$ and the cancellation ledger both turn on the response $e$ being an *effect record* rather than raw API bytes — said twice in the body and pinned down nowhere, though it is the interface that makes both tractable. The minimal shape is small: roughly
+
+$$e = (\mathsf{tool\_id},\ \mathsf{action\_id},\ \mathsf{status},\ \mathsf{effects},\ \mathsf{time}), \quad \mathsf{status}\in\{\mathsf{committed},\mathsf{rolled\_back},\mathsf{partial},\mathsf{none},\mathsf{unknown}\}, \quad \mathsf{effects}=[(\mathsf{resource},\mathsf{op},\mathsf{reversible})].$$
+
+Each field is forced by something the body already needs. The $\mathsf{action\_id}$ lets $\rho$ match a response to the in-flight action $\gamma$ authorized, and lets the ledger say which actions are still open — without it the $\mathsf{unknown}$/orphan accounting has nothing to key on. The $\mathsf{status}$ must carry $\mathsf{unknown}$ as a value *distinct* from $\mathsf{committed}$ and from $\mathsf{none}$, because that distinction is the whole content of the cancellation ledger: "did not confirm" is not "did not happen" ($\mathsf{none}$ is *never launched* — the record of the distinguished no-op $e_0$ a $\gamma$-rejection forces, which is how a bounce at the gate enters the ledger at all — distinct in turn from $\mathsf{rolled\_back}$, which launched and was undone: conflating those erases the difference between a gate that held and a compensation that worked). The $\mathsf{reversible}$ bit on each effect is what lets the gate know which effects are irreversible — the predicate the gate-placement entry leans on ("anything irreversible must be gated at authorization") but cannot evaluate unless the record carries it (a bit is the minimal honest form, not the final one: real effects are reversible *until* — an unsend window, a force-push until someone fetched, a row until the backup rotates — so the mark wants to be a $(\mathsf{reversible\_until}, \mathsf{cost})$ pair, a refinement the open-interface caveat below already licenses). And $\rho$ writes the record into $s$ (the ledger lives in the state), which is what lets the next step's $\gamma$, and any owner-side compensation, read it at all. The exact fields are an **open interface, not a result**: bash, HTTP, a filesystem, and a database expose effects at wildly different granularity, and a record uniform across them is a real design problem this document does not resolve — it fixes only what the record must *support* (match by $\mathsf{action\_id}$, the $\mathsf{committed}$/$\mathsf{none}$/$\mathsf{unknown}$ trichotomy, and a reversibility mark), since without those three $\rho$ and the cancellation semantics lose their grip.
+
+**Derived and durable state (compaction and memory).** Two mechanisms let data re-enter the context long after it arrived: compaction, which replaces transcript with a summary when the conversation outgrows what $\pi$ can lower, and memory, which persists records across sessions. Both are transformations of state that produce state, and both therefore raise a question the body's partition answers only if one more closure property is stated: **provenance is a property of the information, not of its position in the pipeline — a transformation's output inherits the meet, in the trusted-writer lattice, of its inputs' labels.** Without that closure, compaction is a laundering channel: a summary of a session that contained an injected page can assert "the user asked to export the database," and the structural-intent check then validates future proposals against a plan the adversary bent — not through $\gamma$, not through $\rho$'s fold of a single $e$, but through the summarizer, which is a learned kernel (it lives in $M_W$, by the standing rule) and so cannot be trusted to preserve a partition it does not know exists. The discipline: summaries of data are data; the control-determining coordinates — plan, grants, what is authorized next — cross a compaction *verbatim* (copied, not paraphrased) or by re-confirmation from the trusted principal — never through the *summarizer*; the model rewrites the plan at plan steps, through the gated fold the body prices, and compaction is not one of them. Memory obeys the same closure twice, at write and at retrieval: the label rides the stored record across sessions, or a poisoned memory is an injection with an arbitrarily long fuse — and retrieval, being learned ($\pi$'s selection factor — adequacy-only behind the never-lower filter), decides what comes back but never what it is trusted *as*. The same test applies at birth: tool catalogs and server-supplied tool descriptions are third-party durable data that arrive dressed as instructions, and the lattice files them on the data side of $s_0$.
+
+One more read-off, this time from irreversibility. *Destructive* compaction — dropping the original transcript once the summary is written — is a side effect against your own state that no later step can undo, and the gate-placement rule ("anything irreversible must be gated at authorization") does not exempt self-directed effects. The granularity preference then says what it said about bash: prefer the instrumented form — originals kept content-addressed, the summary an index and a cache rather than an authority, re-derivable when the $\pi$-sufficiency probe (*How this could be wrong*) says the summary dropped what mattered. A summary you can audit against its source is a lowering; a summary that replaced its source is a fait accompli.
+
+**Composition (harness trees).** The cancellation entry already walked a tree — cancel flowing down, drains flowing up — and "a bash invocation that may itself be a harness" has hovered since the disposition trinary; what is missing is only the statement that makes both ordinary. From the parent's seat, a child harness *is* a $Q_E$ component: spawning it is an action authorized by $\gamma$ like any other, and the entire child run — its own $\pi, \gamma, \rho$, its own coins, its own halt — is one environment draw whose response $e$ is the child's terminal ledger. The law is four correspondences. The child's halting time is the parent's per-step *cost*: a parent certificate consumes a bound on $\mathbb{E}[\tau_H^{\mathrm{child}}]$ — the budget handed down at spawn, which the child's own budget-counter certificate discharges — or the parent's drift is uncontrolled however good its own $\hat V$. The child's ledger is the parent's *effect record*: the child's $e$ carries the $\mathsf{committed}/\mathsf{none}/\mathsf{unknown}$ accounting upward — which is what already let the cancellation entry make compensation the owner's job; the interface was this all along. And the child's non-accepting halts are the parent's *partial failures*: a refused child folds back as a response the parent routes around, not an exception that unwinds it. And the child's admissible effects are the parent's *$\Pi$-restriction*: the spawn grant bounds what the child can reach — the ledger reports what *happened*, the grant bounds what *could* — which is how safety composes without the parent ever reading the child's gate; the attenuation below is this correspondence stated as a rule. Read this way, the gate-granularity discipline and the tree are one preference: an instrumented child — budgeted, ledgered, cancellable — *is* the bounded, cancellable $Q_E$ the trinary prefers, and an opaque bash invocation is an un-annotated child you declined to instrument. Nesting adds no primitive on the environment side either: the parent never sees the child's gate and does not need to — it gates the spawn, prices the budget, folds the ledger, and the child's internal guarantees surface only as the shape of $e$. Nothing fixes one level: the tree recurses, budgets subdivide, ledgers concatenate upward, and the cooperative drain of cancellation is this law read under a cancel signal.
+
+The tree leaves one seat unassigned: who plays trusted principal for a *child*? The parent — but with derived authority, not original, and the derivation is the narrow-only rule read along the spawn edge: **authority attenuates monotonically down the tree.** A spawn may grant the child any subset of the parent's own grants and nothing outside them; budgets subdivide, scopes narrow, and no edge widens. When a child asks-the-owner, the parent may answer from authority it already holds — that is attenuation working as designed — but a request beyond the parent's grants routes *up*, ultimately to the root principal, because a parent improvising an answer it was never granted is a learned kernel widening authorization: precisely what the gate-placement rule forbids a judge, and being a parent confers no exemption. The corollary is worth one sentence: a fully autonomous run is one whose root principal is unreachable, so the tree's only widening channel is closed and authorization is frozen at launch — not a limitation of the formalism but the honest price of the word *autonomous*.
+
+The pattern generalizes, and that is the point of the appendix. Nothing here added a primitive: the cancel is a signal in $s$, the gate closes by the rule it already follows, the in-flight disposition is forced by irreversibility, $H_{\mathrm{cancel}}$ is a subclass of an existing terminal set, and compensation is an ordinary owner-issued action — and the later entries kept the promise: resume re-enters $T$ at a persisted $s$, the batch gate was always in $\gamma$'s domain, provenance closure is the lattice's meet, attenuation is narrow-only read along an edge, and per-action capability is the gate's decision made enforceable. Every practical concern that earns a place here should resolve the same way — not new machinery, but the discipline the existing objects already imply, made explicit. Cancellation and resume, gate placement and the batch gate, effect records and the state derived from them, composition and delegation — those are the worked instances; the rest of the model is the same exercise.
+
+
+---
+
+*The ramblings of Claude and Patrick.*

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+      whether in tort (including negligence), contract, or otherwise,
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+      defend, and hold each Contributor harmless for any liability
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+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
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+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
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+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
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+
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+
+   Unless required by applicable law or agreed to in writing, software
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+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

NOTICE

@@ -0,0 +1,7 @@
+Turnstone
+Copyright 2025-2026 Patrick Buckley
+
+Licensed under the Apache License, Version 2.0; see the LICENSE file.
+
+Third-party software bundled with this distribution is listed in the
+THIRD-PARTY-NOTICES file; each component remains under its own license.

QUICKSTART.md

@@ -1,92 +1,107 @@
-# Bootstrap Wizard
+# Quickstart
 
-Interactive, AI-guided setup for Turnstone deployments. Instead of manually
-editing `.env` files and reading deployment docs, the wizard walks you through
-every decision conversationally and generates all the config files for you.
+Install Turnstone, then diagnose it with `turnstone-doctor` if anything looks off.
 
-## Quick Start
+## Install
+
+The one-line installer autodetects your distro (Ubuntu/Debian, Fedora/RHEL,
+Arch, and WSL), installs git + Docker if missing, generates secrets, picks free
+ports, and starts the stack:
 
 ```bash
-turnstone-bootstrap
+curl -fsSL https://raw.githubusercontent.com/turnstonelabs/turnstone/main/run.sh | bash
 ```
 
-That's it — no flags, no arguments. The wizard prompts for everything.
+Re-running is safe — it updates the checkout and keeps your existing `.env`.
+When it finishes it prints the dashboard URL and how to create the first admin
+user.
 
-## How It Works
+**Other ways to install**
 
-1. **Pick a model** — Choose OpenAI, Anthropic, or a local/vLLM endpoint to
-   power the wizard. Local endpoints auto-detect available models.
-2. **Answer questions** — The AI walks you through deployment mode, LLM
-   provider, database, authentication, ports, and optional features.
-3. **Review generated files** — Each file is previewed before writing. You
-   confirm or reject every write.
-4. **Start the stack** — The wizard prints the exact `docker compose` command
-   and a `setup.sh` script to create your first admin user, roles, and policies.
+- **Already have Docker?** Clone the repo and `docker compose up` for the full
+  local cluster, or `docker compose -f turnstone/deploy/compose.yaml up` for the
+  released single-node stack. See [docs/docker.md](docs/docker.md).
+- **Python package:** `pip install turnstone` (add `--pre` for the experimental
+  track), then run `turnstone-server` / `turnstone-console` directly. See the
+  [README](README.md#quickstart).
 
-## What Gets Generated
+## Diagnose: `turnstone-doctor`
 
-| File | Purpose |
+`turnstone-doctor` is an LLM-backed assistant that inspects a **running**
+Turnstone install and helps you troubleshoot it. It is **read-only** — it
+investigates and tells you the exact commands to fix things, but never changes
+your system. (Installation is the installer's job, not the doctor's.)
+
+```bash
+# From a host that has the turnstone package installed:
+turnstone-doctor
+
+# For a Docker install from run.sh (no package on the host), run it with pipx:
+pipx run --spec turnstone turnstone-doctor --dir ~/turnstone
+```
+
+### What it does
+
+1. **Preflight** — detects how Turnstone is installed here (docker-compose,
+   systemd/bare-metal, pip, or a source checkout) by probing for `config.toml`
+   files, `TURNSTONE_*` environment variables, compose files, and systemd units.
+2. **Self-configures its LLM** — it powers its own brain from your cluster's
+   *own* model configuration (env / `config.toml` / the database). Whether that
+   works is the first diagnostic: success means your LLM backend is healthy; if
+   it can't, that's surfaced as finding #1 and it falls back to asking you for a
+   provider and key so it can still help.
+3. **Version check** — reports the installed version, version drift across your
+   cluster's nodes, and the latest upstream stable/experimental releases.
+4. **Interactive diagnosis** — it reads logs, `/health`, `docker compose ps`,
+   `systemctl`, config, and ports to pin down problems like a node not joining
+   the console, an unreachable database, a down model backend, port conflicts,
+   or a JWT-secret mismatch — then hands you the precise remediation commands.
+
+### Flags
+
+| Flag | Purpose |
 |------|---------|
-| `.env` | All environment variables for `compose.yaml` |
-| `setup.sh` | Post-start script: creates admin user, roles, tool policies, prompt templates via the API |
-| `docker-compose.override.yaml` | Only if customizations beyond env vars are needed |
+| `--dir PATH` | Install directory to inspect (default: current directory) |
+| `--report` | Print the deterministic preflight report and exit — no LLM key needed |
+| `--offline` | Skip the upstream GitHub version check |
 
-## Requirements
+`--report` is the fastest way to get a health snapshot (and to share one when
+asking for help) — it never needs an API key:
 
-- **Python 3.11+** with turnstone installed (`pip install turnstone`)
-- **An LLM API key** — for the wizard itself (OpenAI, Anthropic, or a local
-  model). This can differ from the LLM your deployment will use.
-- **Docker & Docker Compose** — needed to run the stack. The wizard detects
-  whether Docker is installed and gives platform-specific install instructions
-  if it's missing. You can still generate config files without Docker.
-
-## Deployment Modes
-
-- **Single-node production** — `docker compose up` against the bundled
-  `turnstone/deploy/compose.yaml`: 1 server + console + channel + PostgreSQL,
-  pulled from ghcr.io. Good for most deployments.
-- **Local multi-node cluster** — clone the repo and run `docker compose up` at
-  the root for a 10-node fleet + console + Caddy + channel, built locally.
-
-See [docs/docker.md](docs/docker.md) for both.
-
-## Example Session
+```bash
+turnstone-doctor --report --dir ~/turnstone
+```
 
 ```
-$ turnstone-bootstrap
+## Install profile
+- Detected kind(s): docker-compose  (primary: docker-compose)
+- Docker daemon reachable: yes
+- Compose files:
+    /home/you/turnstone/compose.yaml
+- Database: backend=postgresql, url=postgresql+psycopg://turnstone:****@postgres:5432/turnstone
+- Candidate health URLs: http://localhost:8080/health, http://localhost:8090/health
 
- Turnstone Bootstrap Wizard  v1.5.0
- ────────────────────────────────────────────────
+## Versions
+- Installed (this tool): 1.7.0a2
+- Cluster nodes: 10 reporting; versions ['1.7.0a2']
+- Version drift across nodes: no
+- Upstream: stable 1.6.9, experimental 1.7.0a2
 
- Which provider for this wizard?
-   [1] OpenAI
-   [2] Anthropic
-   [3] OpenAI-compatible (local/vLLM)
-
- > 3
-
- Base URL [http://localhost:8000/v1]:
- API key (press Enter for 'none'):
-
- Querying http://localhost:8000/v1 for available models...
- Found model: Qwen/Qwen3-32B
-
- Connected to Qwen/Qwen3-32B. Handing off to AI assistant...
-
-> (AI walks you through the rest interactively)
+## LLM backend (ok)
+- resolved Qwen/Qwen3-32B via openai-compatible @ http://host.docker.internal:8000/v1
 ```
 
+Secrets (JWT secret, database password, API keys) are always redacted in the
+report and in anything the doctor reads.
+
 ## Tips
 
-- **Re-run safely** — running the wizard again detects your existing `.env`
-  and offers to update it rather than overwriting.
-- **Duplicate writes are skipped** — if the LLM tries to write the same file
-  twice with identical content, it's silently ignored.
-- **Type `quit` to exit** at any time during the conversation.
-- **Ctrl+C** is handled gracefully — press once to interrupt, twice to exit.
+- **Type `quit`** to exit the conversation; **Ctrl+C** interrupts (twice to quit).
+- **Point it at the right install** with `--dir` when you run it from elsewhere.
+- **(Re)installing or adding nodes?** Use the installer (`run.sh`), not the doctor.
 
 ## See Also
 
-- [Docker Deployment](docs/docker.md) — manual compose setup and profiles
+- [Docker Deployment](docs/docker.md) — compose stacks, ports, and bare-metal nodes
 - [Security](docs/security.md) — auth architecture and token types
 - [Governance](docs/governance.md) — roles, policies, and templates

README.md

@@ -3,7 +3,7 @@
 [![CI](https://github.com/turnstonelabs/turnstone/actions/workflows/ci.yml/badge.svg)](https://github.com/turnstonelabs/turnstone/actions/workflows/ci.yml)
 [![PyPI](https://img.shields.io/pypi/v/turnstone)](https://pypi.org/project/turnstone/)
 [![Python](https://img.shields.io/pypi/pyversions/turnstone)](https://pypi.org/project/turnstone/)
-[![License](https://img.shields.io/badge/license-BSL--1.1-blue)](LICENSE)
+[![License](https://img.shields.io/badge/license-Apache--2.0-blue)](LICENSE)
 [![Discord](https://img.shields.io/badge/Discord-join%20us-5865F2?logo=discord&logoColor=white)](https://discord.gg/Nh3bWMacaq)
 
 Self-hosted, local-first orchestration for tool-using AI agents. Give LLMs real tools — shell, files, search, web — and run them across your own cluster with direct HTTP routing and interactive interfaces. Your code, your models, your data stay on hardware you control: no telemetry, no phone-home.
@@ -14,6 +14,14 @@ Self-hosted, local-first orchestration for tool-using AI agents. Give LLMs real
 
 Named after the [Ruddy Turnstone](https://en.wikipedia.org/wiki/Ruddy_turnstone) (*Arenaria interpres*) — a shorebird that flips stones to discover what's hiding underneath.
 
+**What is a harness?**
+
+```
+ℋ :  s_{n+1} ~ T(s_n)   for n < τ*,    T = ρ ∘ (M_W ∘ π, E)
+```
+
+[**the hypothesis →**](HYPOTHESIS.md)
+
 ### Release Tracks
 
 | Track | Install | Docker | Description |
@@ -27,7 +35,7 @@ See [docs/releasing.md](docs/releasing.md) for the full release process.
 
 Turnstone gives LLMs tools — shell, files, search, web, planning — and orchestrates multi-turn conversations where the model investigates, acts, and reports.
 
-- **Local-first & private** — runs entirely on hardware you control, with no telemetry and no phone-home. Point it at local models (vLLM, llama.cpp, Ollama) or commercial APIs you hold the keys to — your prompts and data never transit a third party you didn't choose.
+- **Local-first & private** — runs entirely on hardware you control, with no telemetry and no phone-home. Point it at local models (vLLM, llama.cpp) or commercial APIs you hold the keys to — your prompts and data never transit a third party you didn't choose.
 - **Bring your own models** — OpenAI-compatible APIs (vLLM, llama.cpp, NIM), the Anthropic Messages API, and Google Gemini, mixed freely per role
 - **Interactive sessions** — terminal CLI or browser UI with parallel workstreams
 - **Cluster dashboard** — real-time view of every node and workstream, with a rendezvous routing proxy
@@ -86,7 +94,7 @@ LLM; add model backends from the console UI.
 For production (released images from ghcr.io, real secrets required), use the
 bundled stack: `docker compose -f turnstone/deploy/compose.yaml up`.
 
-See [QUICKSTART.md](QUICKSTART.md) for the bootstrap wizard and [docs/docker.md](docs/docker.md) for Docker configuration.
+See [QUICKSTART.md](QUICKSTART.md) for the install + troubleshooting walkthrough and [docs/docker.md](docs/docker.md) for Docker configuration.
 
 ### Programmatic (SDK)
 
@@ -117,7 +125,7 @@ Built-in tools for shell, files, search, web, memory, notifications, and autonom
 | `turnstone-channel` | Channel gateway (Discord and Slack adapters) |
 | `turnstone-admin` | User/token management CLI |
 | `turnstone-eval` | Eval harness for prompt/tool optimization |
-| `turnstone-bootstrap` | LLM-guided setup wizard |
+| `turnstone-doctor` | LLM-backed cluster diagnostics |
 
 ### Diagrams
 
@@ -169,4 +177,4 @@ Questions, ideas, or want to show what you're building? Join us on Discord:
 
 ## License
 
-[Business Source License 1.1](LICENSE) — free for all use except hosting as a managed service. Converts to Apache 2.0 on 2030-03-01.
+[Apache License 2.0](LICENSE), as of version 1.6.0. Versions 1.5.x and earlier remain under the Business Source License 1.1 they shipped with.

THIRD-PARTY-NOTICES

@@ -2,11 +2,11 @@ Turnstone — Third-Party Notices
 
 This file contains the licenses and notices for third-party software bundled
 with Turnstone. Each bundled dependency retains its original license; the
-Turnstone BUSL-1.1 license does not apply to these components.
+Turnstone Apache-2.0 license does not apply to these components.
 
 ================================================================================
 
-KaTeX 0.16.38
+KaTeX 0.17.0
 https://katex.org/
 https://github.com/KaTeX/KaTeX
 
@@ -70,7 +70,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ================================================================================
 
-Mermaid 11.13.0
+Mermaid 11.15.0
 https://mermaid.js.org/
 https://github.com/mermaid-js/mermaid
 
@@ -98,7 +98,7 @@ SOFTWARE.
 
 ================================================================================
 
-hls.js 1.6.15
+hls.js 1.6.16
 https://github.com/video-dev/hls.js
 
 Copyright 2017 Dailymotion

compose.yaml

@@ -29,10 +29,11 @@
 # Fewer nodes (lighter machines):
 #     docker compose up postgres console caddy channel node-1 node-2 node-3
 #
-# Join a bare-metal host: Postgres is published on 127.0.0.1:5432, so a
-# turnstone-server running directly on this machine (e.g. to use a local GPU)
-# can join the same cluster. Keep the secret + connection settings in
-# ~/.config/turnstone/config.toml (chmod 0600 — the loader warns otherwise):
+# Join a bare-metal host: a turnstone-server running OUTSIDE compose (e.g. to use
+# a local GPU) can join this cluster. Postgres, the console's ACME endpoint, and
+# SearxNG are published on 127.0.0.1 so a node on THIS machine reaches them via
+# localhost. Keep secrets in ~/.config/turnstone/config.toml (chmod 0600 — the
+# loader warns otherwise):
 #     [auth]
 #     jwt_secret = "dev-only-insecure-jwt-secret-change-me-for-real-deployments"
 #     [database]
@@ -41,10 +42,19 @@
 #     [api]
 #     base_url = "http://localhost:8000/v1"
 #     api_key = "dummy"
+#     [tls]              # only if the cluster runs mTLS
+#     enabled = true
 # then run (node identity isn't a secret, so it stays on the command line):
-#     TURNSTONE_NODE_ID=host-1 TURNSTONE_ADVERTISE_URL=http://host.docker.internal:8080 \
+#     TURNSTONE_NODE_ID=host-1 \
+#       TURNSTONE_ADVERTISE_URL=http://host.docker.internal:8080 \
+#       TURNSTONE_CONSOLE_URL=http://localhost:8090 \
+#       TURNSTONE_SEARXNG_URL=http://localhost:8081 \
 #       turnstone-server --host 0.0.0.0 --port 8080
-# It registers in Postgres and the console reaches it back via host.docker.internal.
+# The node registers in Postgres, auto-enrolls its mTLS cert from the console's
+# ACME endpoint (when the cluster runs mTLS), and the console collector reaches
+# it back via host.docker.internal. To join from ANOTHER machine, set
+# TURNSTONE_HOST_IP to this host's LAN IP and use it in the URLs above (and the
+# node's TURNSTONE_ADVERTISE_URL = the NODE host's IP) — see docs/docker.md.
 # =============================================================================
 
 name: turnstone
@@ -93,13 +103,14 @@ services:
       # INSECURE dev default — override POSTGRES_PASSWORD in .env for real use.
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-turnstone}
       PGDATA: /var/lib/postgresql/data
-    # Published on localhost so a bare-metal turnstone-server running on THIS
-    # host can join the cluster (see "Join a bare-metal host" in the header).
-    # Bound to 127.0.0.1 by default; set POSTGRES_BIND=0.0.0.0 to let another
-    # machine connect — but set a real POSTGRES_PASSWORD first, or you'll expose
-    # a database with the insecure default password to your network.
+    # Published so a bare-metal turnstone-server can join the cluster (see "Join
+    # a bare-metal host" in the header). Bound to 127.0.0.1 by default (same-host
+    # nodes only); set TURNSTONE_HOST_IP to this host's LAN IP to let another
+    # machine connect — but set a real POSTGRES_PASSWORD first, or you'll expose a
+    # database with the insecure default password to your network. (The legacy
+    # POSTGRES_BIND is still honored as a fallback when TURNSTONE_HOST_IP is unset.)
     ports:
-      - "${POSTGRES_BIND:-127.0.0.1}:${POSTGRES_PORT:-5432}:5432"
+      - "${TURNSTONE_HOST_IP:-${POSTGRES_BIND:-127.0.0.1}}:${POSTGRES_PORT:-5432}:5432"
     volumes:
       - postgres-data:/var/lib/postgresql/data
     networks:
@@ -120,10 +131,12 @@ services:
   # turnstone-console — cluster dashboard. Reach it ONLY through Caddy at
   # https://localhost:8443 (see the caddy service below).
   #
-  # The console port (8090) is deliberately NOT published to the host: a plain
-  # HTTP/1.1 origin caps the browser at 6 connections, which starves the
-  # dashboard's per-pane SSE streams. Caddy serves the browser over HTTP/2
-  # (multiplexed) and proxies to console:8090 internally, so the cap is gone.
+  # Browsers must reach the dashboard through Caddy (https://localhost:8443): a
+  # plain HTTP/1.1 origin caps the browser at 6 connections, which starves the
+  # dashboard's per-pane SSE streams, whereas Caddy serves HTTP/2 (multiplexed)
+  # and proxies to console:8090 internally. The console's :8090 is published
+  # below ONLY so bare-metal nodes can reach the plain-HTTP ACME enrollment
+  # endpoint — don't point a browser at it.
   #
   # The single `build:` here produces the turnstone:local image every other
   # service reuses. extra_hosts lets the console reach a bare-metal server
@@ -138,6 +151,14 @@ services:
       - turnstone-console
       - --host=0.0.0.0
       - --port=8090
+    # Publishes the console's plain-HTTP listener so a bare-metal node can reach
+    # the ACME endpoint, fetch the CA, and enroll its cert (the console serves
+    # HTTP here even under mTLS). Bound to 127.0.0.1 by default; setting
+    # TURNSTONE_HOST_IP exposes the WHOLE console HTTP API — including the
+    # cert-issuing ACME endpoint — on that interface, so the JWT secret's
+    # strength is the only gate. Browsers use Caddy :8443, never this port.
+    ports:
+      - "${TURNSTONE_HOST_IP:-127.0.0.1}:8090:8090"
     environment:
       TURNSTONE_JWT_SECRET: *jwt-secret
       TURNSTONE_DB_BACKEND: *db-backend
@@ -219,6 +240,13 @@ services:
   # -------------------------------------------------------------------
   searxng:
     image: searxng/searxng:${SEARXNG_IMAGE_TAG:-latest}
+    # Published so a bare-metal node's web_search can reach it. SearxNG has NO
+    # auth, so it is bound to 127.0.0.1 by default; setting TURNSTONE_HOST_IP
+    # exposes it on that interface — an open search proxy on your LAN, which also
+    # triggers the SearxNG AGPL-3.0 §13 source-offer obligation (see docs/docker.md).
+    # In-compose nodes always use the internal http://searxng:8080 and ignore this.
+    ports:
+      - "${TURNSTONE_HOST_IP:-127.0.0.1}:${SEARXNG_API_PORT:-8081}:8080"
     volumes:
       - ./turnstone/deploy/searxng:/etc/searxng:ro
       - searxng-cache:/var/cache/searxng # favicon + internal SQLite cache (survives restarts)

deploy/systemd/README.md

@@ -0,0 +1,72 @@
+# Running a bare-metal turnstone-server under systemd
+
+These units run a `turnstone-server` **outside** Docker (e.g. on a box with a
+local GPU) so it joins an existing cluster — typically the docker-compose stack
+in [`compose.yaml`](../../compose.yaml). They are the hardened, production-shaped
+counterpart to the quick `turnstone-server …` invocation in
+[`docs/docker.md`](../../docs/docker.md) ("Join a bare-metal host").
+
+| File | Purpose |
+|------|---------|
+| `turnstone-server.service` | The hardened server unit (sandboxed; secrets via `config.toml`). |
+| `turnstone.slice` | Shared memory/process budget for colocated Turnstone units. |
+| `turnstone-server.service.d/node.conf.example` | Per-host identity + cluster URLs drop-in (no secrets). |
+
+## Cluster-side prerequisite
+
+The compose stack must publish Postgres, the console's ACME endpoint, and SearxNG
+on an address the bare-metal host can reach. Start it with `TURNSTONE_HOST_IP`
+set to the compose host's LAN IP (default `127.0.0.1` keeps everything host-local):
+
+```bash
+TURNSTONE_HOST_IP=<compose-host-ip> docker compose up -d
+```
+
+## Install (run as root on the bare-metal host)
+
+```bash
+# 1. A dedicated, unprivileged user.
+useradd --system --no-create-home --shell /usr/sbin/nologin turnstone
+
+# 2. Install turnstone into a venv at /opt/turnstone-venv (lacme/mTLS is a core dep).
+uv venv /opt/turnstone-venv --python 3.12
+uv pip install --python /opt/turnstone-venv 'turnstone @ git+https://github.com/turnstonelabs/turnstone'
+#   …or from a local checkout:  uv pip install --python /opt/turnstone-venv /path/to/turnstone
+
+# 3. Secrets — match the cluster's JWT secret + DB credentials (kept out of env).
+install -d -m 750 -o turnstone -g turnstone /etc/turnstone
+cat > /etc/turnstone/config.toml <<'TOML'
+[auth]
+jwt_secret = "<same secret as the cluster>"
+[database]
+backend = "postgresql"
+url = "postgresql+psycopg://turnstone:<password>@<compose-host-ip>:5432/turnstone"
+[api]
+base_url = "http://localhost:8000/v1"   # a real model backend is configured in the console UI
+api_key = "dummy"
+TOML
+chown turnstone:turnstone /etc/turnstone/config.toml
+chmod 600 /etc/turnstone/config.toml
+
+# 4. Units + per-host drop-in.
+cp turnstone-server.service turnstone.slice /etc/systemd/system/
+install -d /etc/systemd/system/turnstone-server.service.d
+cp turnstone-server.service.d/node.conf.example \
+   /etc/systemd/system/turnstone-server.service.d/node.conf
+$EDITOR /etc/systemd/system/turnstone-server.service.d/node.conf   # set the addresses
+
+# 5. Go.
+systemctl daemon-reload
+systemctl enable --now turnstone-server.service
+journalctl -u turnstone-server -f          # watch it register + (if the cluster runs mTLS) enroll
+```
+
+`tls.enabled` is **not** set here — a joining node inherits it from the cluster's
+shared settings (the database). If the cluster runs mTLS, the node auto-enrolls a
+cert from the console's ACME endpoint and re-advertises itself over `https://`.
+
+> **mTLS + cross-host caveat:** a node on a *different* host than the console
+> currently can't complete ACME enrollment — the console advertises an
+> unroutable in-container address in its ACME directory
+> ([turnstonelabs/lacme#22](https://github.com/turnstonelabs/lacme/issues/22)).
+> Same-host bare-metal nodes, and any node in a non-mTLS cluster, are unaffected.

deploy/systemd/turnstone-server.service

@@ -0,0 +1,85 @@
+# Run a bare-metal turnstone-server as a systemd service so it joins a cluster
+# (e.g. the docker-compose stack) from outside Docker — typically to use a local
+# GPU. Install steps + the cluster-side prerequisites are in deploy/systemd/README.md
+# and docs/docker.md ("Join a bare-metal host"). Per-host identity + the cluster
+# URLs go in a drop-in (see node.conf.example); secrets go in config.toml.
+[Unit]
+Description=Turnstone server (chat workstreams + LLM gateway)
+Documentation=https://github.com/turnstonelabs/turnstone
+# Postgres is required. After= orders against a colocated postgresql.service
+# when present and silently no-ops otherwise (the cluster DB is usually remote).
+After=network.target postgresql.service
+StartLimitIntervalSec=60
+StartLimitBurst=5
+
+[Service]
+Type=exec
+User=turnstone
+Group=turnstone
+
+# Secrets live in config.toml — JWT secret, Postgres URL+password, LLM API key —
+# kept out of os.environ so a prompt-injected tool can't dump them via `env`.
+Environment=TURNSTONE_CONFIG=/etc/turnstone/config.toml
+Environment=TURNSTONE_LOG_LEVEL=info
+
+Slice=turnstone.slice
+
+# Per-host node identity + cluster wiring (TURNSTONE_NODE_ID / _ADVERTISE_URL /
+# _CONSOLE_URL / _SEARXNG_URL) go in a drop-in, not here — see node.conf.example.
+
+StateDirectory=turnstone
+StateDirectoryMode=0750
+LogsDirectory=turnstone
+LogsDirectoryMode=0750
+WorkingDirectory=/var/lib/turnstone
+
+# --host 0.0.0.0 so the console collector + peer nodes can dial this node back
+# at its advertised address. (A single-node, Caddy-fronted install can use
+# 127.0.0.1 instead.) Rewrite --port if :8080 is already taken on the host.
+ExecStart=/opt/turnstone-venv/bin/turnstone-server --host 0.0.0.0 --port 8080
+
+Restart=on-failure
+RestartSec=5s
+TimeoutStartSec=120
+TimeoutStopSec=30
+KillSignal=SIGTERM
+KillMode=mixed
+
+# --- Resource limits ---
+# SSE keeps an fd per active workstream + outbound LLM stream + MCP stdio pipe.
+LimitNOFILE=65535
+LimitNPROC=8192
+TasksMax=8192
+LimitCORE=0
+
+# --- Hardening ---
+NoNewPrivileges=true
+CapabilityBoundingSet=
+AmbientCapabilities=
+UMask=0027
+PrivateTmp=true
+# PrivateDevices=true  — disabled: GPU access via /sys/class/drm
+ProtectSystem=strict
+ProtectHome=true
+ProtectKernelTunables=true
+ProtectKernelModules=true
+ProtectKernelLogs=true
+ProtectControlGroups=true
+ProtectClock=true
+ProtectHostname=true
+RestrictNamespaces=true
+RestrictRealtime=true
+RestrictSUIDSGID=true
+RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
+LockPersonality=true
+MemoryDenyWriteExecute=true
+SystemCallArchitectures=native
+SystemCallFilter=@system-service
+SystemCallFilter=~@privileged @mount
+
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=turnstone-server
+
+[Install]
+WantedBy=multi-user.target

deploy/systemd/turnstone-server.service.d/node.conf.example

@@ -0,0 +1,25 @@
+# Per-host node identity + cluster wiring for a bare-metal turnstone-server.
+# Copy to /etc/systemd/system/turnstone-server.service.d/node.conf and edit the
+# addresses, then `systemctl daemon-reload`. Identity + URLs are NOT secrets, so
+# they live here; the JWT secret + DB URL live in /etc/turnstone/config.toml.
+#
+# Addresses below use RFC 5737 documentation IPs — replace them:
+#   <this-host>     = the bare-metal host's own LAN IP (what the console dials back)
+#   <compose-host>  = the host running the cluster / docker-compose stack, started
+#                     with TURNSTONE_HOST_IP=<compose-host> so :8090 and :8081 are
+#                     published on its LAN interface (see docs/docker.md).
+[Service]
+# Unique node id (defaults to the hostname if unset).
+Environment=TURNSTONE_NODE_ID=host-1
+
+# The address peers + the console collector dial back. Auto-upgrades to https://
+# once the node enrolls its mTLS cert.
+Environment=TURNSTONE_ADVERTISE_URL=http://192.0.2.10:8080
+
+# The cluster console's reachable plain-HTTP ACME/API endpoint. A bare-metal node
+# can't resolve the in-cluster name (console:8090), so point it at the published
+# port; turnstone-server honors this for cert enrollment.
+Environment=TURNSTONE_CONSOLE_URL=http://192.0.2.1:8090
+
+# The cluster's published SearxNG, for the web_search tool.
+Environment=TURNSTONE_SEARXNG_URL=http://192.0.2.1:8081

deploy/systemd/turnstone.slice

@@ -0,0 +1,15 @@
+# Shared resource budget for the colocated Turnstone units. Without a slice each
+# unit's MemoryMax= is enforced independently — three units at 85% each can sum
+# to 255% of host RAM before any throttles. Under a shared slice the cap is
+# hierarchical: the slice ceiling is the real limit. (A bare-metal node that runs
+# only turnstone-server still benefits — and keeps the unit's Slice= reference
+# valid.) Adjust if the host runs other meaningful workloads alongside Turnstone.
+[Unit]
+Description=Turnstone services slice (server + console + channel)
+Documentation=https://github.com/turnstonelabs/turnstone
+Before=slices.target
+
+[Slice]
+MemoryHigh=70%
+MemoryMax=85%
+TasksMax=16384

docker/healthcheck.py

@@ -2,13 +2,69 @@
 """Health check for turnstone containers.
 
 Usage: healthcheck.py <url>
-Exit 0 if the endpoint returns {"status": "ok"}, exit 1 otherwise.
-Uses only stdlib — no pip dependencies required.
+Exit 0 if the endpoint returns {"status": "ok"} or {"status": "degraded"},
+exit 1 otherwise. Uses only stdlib — no pip dependencies required.
+
+When the node serves mTLS (tls.enabled), a plain-HTTP probe is rejected at
+the socket, so on failure this script retries over HTTPS, presenting the
+node's own certificate as the client cert and pinning the cluster CA. The
+PEM files are the ones the server writes at boot under
+$TURNSTONE_TLS_PEM_DIR (default: <tmpdir>/turnstone-tls). The host is
+rewritten to "localhost" for the TLS attempt because the internal CA issues
+DNS SANs only — certificate verification rejects a literal-IP dial.
+
+When mTLS is disabled (the default), the plain probe succeeds and nothing
+here changes: the PEM directory is never consulted.
 """
 
 import json
+import os
+import ssl
 import sys
+import tempfile
 import urllib.request
+from pathlib import Path
+from urllib.parse import urlsplit, urlunsplit
+
+
+def _check(url: str, context: ssl.SSLContext | None = None) -> None:
+    """Probe one URL; raise if unreachable or the payload is unhealthy."""
+    req = urllib.request.Request(url, method="GET")
+    with urllib.request.urlopen(req, timeout=5, context=context) as resp:
+        data = json.loads(resp.read().decode())
+    if data.get("status") not in ("ok", "degraded"):
+        raise RuntimeError(f"unhealthy payload: {data}")
+
+
+def _pem_root() -> Path:
+    """PEM runtime root.
+
+    Must mirror turnstone.core.tls.tls_pem_runtime_dir — this script is
+    standalone stdlib and cannot import turnstone; a drift-guard test in
+    tests/test_docker_healthcheck.py pins the two together.
+    """
+    root_env = os.environ.get("TURNSTONE_TLS_PEM_DIR")
+    return Path(root_env) if root_env else Path(tempfile.gettempdir()) / "turnstone-tls"
+
+
+def _find_pem_dir() -> Path | None:
+    """Locate the newest complete PEM dir written by the server at boot."""
+    root = _pem_root()
+    candidates = [
+        d
+        for d in root.glob("lacme-pem-*")
+        if all((d / name).is_file() for name in ("fullchain.pem", "key.pem", "ca.pem"))
+    ]
+    if not candidates:
+        return None
+    return max(candidates, key=lambda d: d.stat().st_mtime)
+
+
+def _tls_url(url: str) -> str:
+    """Rewrite scheme to https and host to localhost, keeping port and path."""
+    parts = urlsplit(url)
+    netloc = f"localhost:{parts.port}" if parts.port else "localhost"
+    return urlunsplit(("https", netloc, parts.path, parts.query, parts.fragment))
 
 
 def main() -> None:
@@ -18,16 +74,24 @@ def main() -> None:
 
     url = sys.argv[1]
     try:
-        req = urllib.request.Request(url, method="GET")
-        with urllib.request.urlopen(req, timeout=5) as resp:
-            data = json.loads(resp.read().decode())
-            if data.get("status") in ("ok", "degraded"):
-                sys.exit(0)
-            print(f"Unhealthy: {data}", file=sys.stderr)
+        _check(url)
+        sys.exit(0)
+    except Exception as plain_exc:
+        pem_dir = _find_pem_dir()
+        if pem_dir is None:
+            print(f"Health check failed: {plain_exc}", file=sys.stderr)
+            sys.exit(1)
+        try:
+            context = ssl.create_default_context(cafile=str(pem_dir / "ca.pem"))
+            context.load_cert_chain(str(pem_dir / "fullchain.pem"), str(pem_dir / "key.pem"))
+            _check(_tls_url(url), context=context)
+            sys.exit(0)
+        except Exception as tls_exc:
+            print(
+                f"Health check failed: plain: {plain_exc}; mtls: {tls_exc}",
+                file=sys.stderr,
+            )
             sys.exit(1)
-    except Exception as exc:
-        print(f"Health check failed: {exc}", file=sys.stderr)
-        sys.exit(1)
 
 
 if __name__ == "__main__":

docs/api-reference.md

@@ -63,7 +63,10 @@ Auth is always enabled. All API endpoints except public paths require a valid to
 Include a token in one of two ways:
 
 - **Bearer header**: `Authorization: Bearer <token>`
-- **Cookie**: `turnstone_auth=<token>` (set automatically by the login endpoint)
+- **Cookie**: the surface-scoped auth cookie — `turnstone_auth_server` on
+  turnstone-server, `turnstone_auth_console` on turnstone-console (set
+  automatically by the login endpoint). The names differ so the two surfaces,
+  when co-hosted on one origin, don't overwrite each other's session.
 
 The server accepts two token types:
 
@@ -102,7 +105,8 @@ Authenticate with credentials and receive a JWT. Accepts two credential formats:
 }
 ```
 
-The response also sets a `turnstone_auth` HttpOnly cookie containing the JWT.
+The response also sets a surface-scoped HttpOnly cookie containing the JWT
+(`turnstone_auth_server` on turnstone-server, `turnstone_auth_console` on turnstone-console).
 
 **Response (failure):** `401`
 
@@ -114,7 +118,8 @@ The response also sets a `turnstone_auth` HttpOnly cookie containing the JWT.
 
 ### `POST /v1/api/auth/logout`
 
-Clears the `turnstone_auth` cookie. No request body required.
+Clears the surface-scoped auth cookie (`turnstone_auth_server` /
+`turnstone_auth_console`). No request body required.
 
 **Response:** `200`
 
@@ -199,7 +204,8 @@ this endpoint.
 }
 ```
 
-The response also sets a `turnstone_auth` HttpOnly cookie containing the JWT.
+The response also sets a surface-scoped HttpOnly cookie containing the JWT
+(`turnstone_auth_server` on turnstone-server, `turnstone_auth_console` on turnstone-console).
 
 **Response (already set up):** `409`
 

docs/architecture.md

@@ -22,7 +22,7 @@ plugs in.
 | `turnstone-eval` | `turnstone.eval` | `NullUI` | Headless evaluation and prompt optimization |
 | `turnstone-channel` | `turnstone.channels.cli` | ChannelAdapter | Channel gateway (Discord, Slack, etc.) |
 | `turnstone-admin` | `turnstone.admin` | — | Offline user and API token management |
-| `turnstone-bootstrap` | `turnstone.bootstrap` | — | LLM-guided setup wizard |
+| `turnstone-doctor` | `turnstone.doctor` | — | LLM-backed cluster diagnostics |
 
 ---
 
@@ -702,7 +702,7 @@ agent_model = "claude"
 
 Each `[models.*]` entry produces a `ModelConfig` with a `provider` field
 (default: `"openai"`). Supported values: `"openai"`, `"anthropic"`, `"google"`,
-and `"openai-compatible"`.
+`"openai-compatible"`, and `"anthropic-compatible"`.
 
 **Per-model sampling overrides:** Each model can specify `temperature`,
 `max_tokens`, and `reasoning_effort` to override the global defaults from
@@ -765,6 +765,63 @@ model = "qwen-3.5-vl"
 supports_vision = true
 ```
 
+**Anthropic-compatible local servers (vLLM `/v1/messages`):** the
+`"anthropic-compatible"` provider drives local servers that expose
+Anthropic's Messages API for arbitrary checkpoints — vLLM's
+`/v1/messages` endpoint, which requires a release with thinking-block
+support in the Anthropic endpoint (post-2026-02-28; verified against
+v0.22.1rc1). The lane reuses `AnthropicProvider` in compat mode: same
+wire translation as the real Anthropic lane, but every model resolves to
+the `_ANTHROPIC_COMPAT_DEFAULT` capabilities (200K context, 64K output,
+`token_param=max_tokens`, `thinking_mode=none`, no native
+web_search/tool_search, no vision) — the static Claude table never
+applies to local checkpoints. `base_url` is required — the server root
+WITHOUT `/v1` (the Anthropic SDK appends `/v1/messages`); a trailing
+`/v1` pasted out of openai-compatible habit is stripped automatically,
+and an empty value fails at client construction rather than falling
+back to the commercial endpoint. Set a
+placeholder `api_key` (e.g. `"dummy"`) for unauthenticated servers. Tool calling
+needs the server started with `--enable-auto-tool-choice
+--tool-call-parser <family>` plus the matching reasoning parser.
+Per-model capability overrides opt in to what the checkpoint actually
+supports:
+
+```toml
+[models.vllm-claude]
+provider = "anthropic-compatible"
+base_url = "http://localhost:8000"   # no /v1 — the SDK appends /v1/messages
+api_key = "dummy"
+model = "deepseek-ai/DeepSeek-V4-Flash"
+
+[models.vllm-claude.capabilities]
+supports_vision = true                    # multimodal checkpoints only
+supports_mid_conversation_system = true   # template-dependent
+context_window = 131072
+```
+
+The reasoning toggle does NOT use Anthropic's `thinking` request param.
+Toggle it through the chat template instead: set `{"chat_template_kwargs":
+{"thinking": false}}` as extra body params in the admin Models
+server-compat section (for this provider the section shows only the
+extra-body field — server type, API surface, and thinking mode are
+openai-compatible-only knobs); the provider forwards it via the SDK's
+`extra_body`.
+
+Verified quirks of vLLM's Anthropic endpoint:
+
+* The `thinking` request param is silently dropped — use
+  `chat_template_kwargs` (above) to control reasoning.
+* `stop_sequences` cut the raw stream wherever the text appears —
+  including inside thinking — and report `end_turn` with
+  `stop_sequence=None`. Turnstone does not send stop sequences from
+  this provider.
+* No cache telemetry: `usage` carries input/output token counts only
+  (no `cache_creation_input_tokens` / `cache_read_input_tokens`).
+* Images require a multimodal checkpoint — text-only models return a
+  500 on image blocks, so `supports_vision` stays opt-in per model.
+* Mid-conversation `role: "system"` turns are template-dependent —
+  opt in per model via `supports_mid_conversation_system`.
+
 **Database model definitions:** On server entry points, models can also be
 defined in the `model_definitions` table (admin Models tab). DB models support
 the same per-model sampling overrides. Config.toml models override DB models
@@ -1134,7 +1191,8 @@ Three hierarchical scopes control endpoint access:
    `/metrics`, `/openapi.json`, `/docs`, `/api/auth/*`, and `/api/auth/setup`
    are always allowed.
 2. **Token extraction** — `Authorization: Bearer <token>` header first, then
-   `turnstone_auth` cookie as fallback.
+   surface-scoped auth cookie (`turnstone_auth_server` on the node server,
+   `turnstone_auth_console` on the console) as fallback.
 3. **Token type detection** — dots in the token indicate JWT; `ts_` prefix
    indicates API token.
 4. **Validation** — JWT signature check or API token hash lookup in storage.

docs/bulk-endpoints.md

@@ -12,7 +12,6 @@ Existing bulk endpoints at time of writing:
 |---------------------------------------------------------|--------------------------|------------------------------------------|
 | `GET  /v1/api/cluster/ws/live?ids=a,b,c`                | bulk read                | `{results, denied, truncated}`           |
 | model tool `spawn_batch`                                 | bulk create (per-item)   | `{results, denied}`                      |
-| `POST /v1/api/workstreams/{ws_id}/stop_cascade`          | cascade mutation         | `{cancelled, failed, skipped}`           |
 | `POST /v1/api/workstreams/{ws_id}/close_all_children`    | cascade mutation         | `{closed, failed, skipped}`              |
 
 ---
@@ -146,7 +145,7 @@ consistently-typed across the read and create cases.
 ```
 
 Where `<bucket>` is the endpoint-specific name for "succeeded" —
-`cancelled` for `stop_cascade`, `closed` for `close_all_children`.
+`closed` for `close_all_children`.
 The three buckets partition the input set exactly once:
 
 | Bucket        | Meaning                                                                       |
@@ -161,20 +160,6 @@ be partial.  `skipped` is pre-resolved — the target is already in
 the terminal state the cascade was aiming at, so it's neither a
 win to report nor a fault to fix.
 
-### Example — `stop_cascade`
-
-```json
-{
-  "status": "ok",
-  "cancelled": ["child-1", "child-3"],
-  "failed":    [],
-  "skipped":   ["child-2"]
-}
-```
-
-A subsequent retry would target only `failed` ids, not `skipped`
-ones — the latter are already done.
-
 ### Example — `close_all_children`
 
 ```json
@@ -186,10 +171,12 @@ ones — the latter are already done.
 }
 ```
 
-Same partition, different success-bucket name.  When `coord_client`
-is unavailable (session loaded but no HTTP client attached — a
-construction bug) every id goes to `failed` so the operator notices
-rather than getting a silent all-skipped response.
+Here the success bucket is `closed`.  A subsequent retry would
+target only `failed` ids, not `skipped` ones — the latter are
+already done.  When `coord_client` is unavailable (session loaded
+but no HTTP client attached — a construction bug) every id goes to
+`failed` so the operator notices rather than getting a silent
+all-skipped response.
 
 ---
 
@@ -232,12 +219,12 @@ rather than getting a silent all-skipped response.
 
 - **Phase 6** shipped `cluster/ws/live` as the first Shape A endpoint
   (`{results, denied, truncated}`).
-- **Phase 7** shipped `stop_cascade` as the first Shape B endpoint
-  (`{cancelled, failed, skipped}`).
+- **Phase 7** introduced the Shape B cascade-mutation envelope
+  (`{<bucket>, failed, skipped}`) for the coordinator's
+  cancel-cascade path.
 - **Phase 8 PR A** shipped `spawn_batch` (Shape A, keyed by idx) and
-  `close_all_children` (Shape B, twin of `stop_cascade`), which
-  crystallised the two-shape-per-semantic-category policy codified
-  here.
+  `close_all_children` (Shape B), which crystallised the
+  two-shape-per-semantic-category policy codified here.
 
 Before adding a third shape, read this doc and argue for why the
 new surface doesn't fit either A or B.  Two idioms in the cluster

docs/coordinator-api-tour.md

@@ -18,7 +18,7 @@ schema changes.
 > auth and the `admin.coordinator` permission.  A session-scoped JWT
 > is minted per login (see [docs/oidc.md](oidc.md) / [docs/security.md](security.md));
 > a service token may call the read paths but destructive governance
-> paths (`/restrict`, `/stop_cascade`, `/close_all_children`) require
+> paths (`/restrict`, `/close_all_children`) require
 > the explicit `admin.coordinator` grant — a service-token owner
 > match isn't enough.
 
@@ -44,7 +44,6 @@ schema changes.
 | 6 | Wait for fan-out             | model-side tool `wait_for_workstream`                       |
 | 7 | Govern                       | `POST /v1/api/workstreams/{ws_id}/trust`                    |
 |   |                              | `POST /v1/api/workstreams/{ws_id}/restrict`                 |
-|   |                              | `POST /v1/api/workstreams/{ws_id}/stop_cascade`             |
 |   |                              | `POST /v1/api/workstreams/{ws_id}/close_all_children`       |
 | 8 | Approve / cancel             | `POST /v1/api/workstreams/{ws_id}/approve`                  |
 |   |                              | `POST /v1/api/workstreams/{ws_id}/cancel`                   |
@@ -53,7 +52,7 @@ schema changes.
 Refer to `/openapi.json` (Swagger UI at `/docs`) on any
 `turnstone-console` process for the authoritative operation ids and
 schemas. Coordinator-only verbs (`/children`, `/trust`, `/restrict`,
-`/stop_cascade`, `/close_all_children`) 404 against `kind=interactive`
+`/close_all_children`) 404 against `kind=interactive`
 rows; the shared verbs (`/send`, `/approve`, `/cancel`, `/events`,
 `/history`, `/open`, `/close`, etc.) work on both kinds.
 
@@ -237,14 +236,21 @@ Key properties:
   tool with a fresh timeout.
 - **Modes** — `mode="any"` returns as soon as one child reaches a
   real terminal state (`idle` / `error` / `closed` / `deleted`);
-  `mode="all"` waits for every polled child.
+  `mode="all"` waits for every polled child to reach a real
+  terminal state.
 - **Progress throttling** — the poll loop runs every 500 ms but the
   SSE emission is diff-on-state-change plus a 5-second heartbeat.  A
   600 s wait generates O(dozens) of progress events, not 1200.
-- **Denied rows** — an id the caller doesn't own (cross-tenant) or a
-  missing row is reported as a `denied` state in the results dict;
-  `mode="any"` won't satisfy on a pure-denied list (the LLM should
-  treat it as a config error, not a completion).
+- **Unresolvable ids** — ws_ids are validated up front (exactly
+  32 hex chars; copy them verbatim): a malformed id fails the call
+  immediately with did-you-mean suggestions and a roster of the
+  coord's children.  An id the caller doesn't own, a missing row, or
+  a child hard-deleted mid-wait is reported as `state="not_found"`
+  and aborts the wait on the tick that observes it (top-level
+  `error` / `not_found` / `children` fields, `complete=false`) — the
+  LLM should fix the id and re-issue, not conclude the child died.
+  Foreign and missing collapse into one shape, so the wait can't be
+  used as an existence oracle.
 
 Prefer `wait_for_workstream` over polling `inspect_workstream` in a
 loop — a wait consumes one assistant turn regardless of how long the
@@ -254,10 +260,10 @@ rounds to a 10× token-efficiency win.
 
 ---
 
-## 7. Governance — trust, restrict, stop_cascade, close_all_children
+## 7. Governance — trust, restrict, close_all_children
 
-These four endpoints let an operator steer a live coordinator session
-mid-flight.  All four emit an audit event tagged
+These three endpoints let an operator steer a live coordinator session
+mid-flight.  All three emit an audit event tagged
 `coordinator.<action>` via the dedicated audit executor so a cascade
 burst can't starve audit writes.
 
@@ -287,28 +293,6 @@ idempotent — calling twice with overlapping lists converges to the
 union.  Revocations don't survive a session close/reopen; operators
 opt in per session.  Cap 256 tool names per request, 128 chars each.
 
-### `POST /stop_cascade` — cancel the subtree
-
-```http
-POST /v1/api/workstreams/{ws_id}/stop_cascade
-{}
-```
-
-Cancels the coordinator's in-flight generation AND dispatches
-`cancel_workstream` through the routing proxy for every direct
-child in the in-memory registry.  Returns:
-
-```json
-{"status": "ok", "cancelled": ["child-1", "child-3"], "failed": [], "skipped": ["child-2"]}
-```
-
-Response uses the [cascade-mutation bulk shape](bulk-endpoints.md):
-`cancelled` = accepted, `failed` = dispatch error worth retrying,
-`skipped` = upstream 404 (already gone — stale registry entry or
-the row was deleted between snapshot and dispatch).  Grandchildren
-aren't touched directly; they sit behind their parent's cancel and
-propagate via the child's SSE stream.
-
 ### `POST /close_all_children` — soft-close the direct fan-out
 
 ```http
@@ -322,16 +306,16 @@ Response:
 {"status": "ok", "closed": ["c-1", "c-2"], "failed": [], "skipped": []}
 ```
 
-Soft-close cascade bounded by the same semaphore as `stop_cascade`.
-The `reason` (up to 512 chars) propagates into each closed child's
-audit + `workstream_config` for postmortem.  Unlike `stop_cascade`
-this does NOT recurse into grandchildren — the model-facing tool
-that pairs with this endpoint asks for a bounded teardown of the
-coordinator's own fan-out.  For a full-subtree teardown, use
-`stop_cascade`.
+Soft-close cascade bounded by a concurrency semaphore.  The `reason`
+(up to 512 chars) propagates into each closed child's audit +
+`workstream_config` for postmortem.  The model-facing tool that
+pairs with this endpoint asks for a bounded teardown of the
+coordinator's own fan-out.  This *soft-closes*; to *cancel* the
+fan-out instead, cancel the coordinator (§8) — a coordinator cancel
+auto-cascades to its direct children.
 
-See [bulk-endpoints.md](bulk-endpoints.md) for why both endpoints
-share the cascade-mutation shape and how it differs from the
+See [bulk-endpoints.md](bulk-endpoints.md) for why `close_all_children`
+uses the cascade-mutation shape and how it differs from the
 `spawn_batch` / `cluster/ws/live` shape.
 
 ---
@@ -349,7 +333,10 @@ POST /v1/api/workstreams/{ws_id}/approve
 {"approved": true, "feedback": null, "always": true}    // always-approve this tool name
 ```
 
-`cancel` drops the in-flight generation but leaves the coordinator
+`cancel` drops the coordinator's in-flight generation and, for a
+coordinator, auto-cascades the cancel to its direct children:
+`cancel_workstream` is dispatched through the routing proxy for
+every direct child in the registry.  The coordinator itself is left
 idle and open for a fresh `send`:
 
 ```http
@@ -366,9 +353,10 @@ POST /v1/api/workstreams/{ws_id}/close
 {}
 ```
 
-Soft-closes the session — state persists, children keep running (use
-`close_all_children` or `stop_cascade` first to wind them down), the
-worker thread exits, SSE streams send a final `stream_end` and
+Soft-closes the session — state persists, children keep running
+(wind them down first with `close_all_children`, or by cancelling
+the coordinator, which cascades the cancel to its direct children),
+the worker thread exits, SSE streams send a final `stream_end` and
 disconnect.  The row is reopenable via
 `POST /v1/api/workstreams/{ws_id}/open` so long as it hasn't been
 deleted.
@@ -383,7 +371,7 @@ deleted.
 - [bulk-endpoints.md](bulk-endpoints.md) — the two bulk-shape
   idioms (`{results, denied, truncated}` vs
   `{<bucket>, failed, skipped}`) used by `cluster/ws/live`,
-  `spawn_batch`, `stop_cascade`, and `close_all_children`.
+  `spawn_batch`, and `close_all_children`.
 - [architecture.md](architecture.md) — cluster-wide architecture
   including how coordinator sessions fit next to node-hosted
   interactive workstreams.

docs/coordinator-skills.md

@@ -77,7 +77,7 @@ or MCP config can do adds to it.  Current members:
 | `delete_workstream`       | wind-down       | Hard-delete one child.  Requires approval.                          |
 | `list_nodes`              | discover        | Enumerate live cluster nodes + capabilities.                        |
 | `skills` (action=find)    | discover        | Browse the skill catalog; opt-in `kind` filter narrows by audience. |
-| `memory`                  | persist         | Orchestration scratchpad keyed by the `coordinator` scope.          |
+| `memory`                  | persist         | Durable orchestration memory (`coordinator` scope, per-user — survives across coordinator sessions). |
 | `notify`                  | broadcast       | Post a status update to a human channel at a narrative beat.        |
 | `tasks`                   | plan            | Orchestrator-only scratchpad.  Children don't see it.               |
 
@@ -168,19 +168,33 @@ Every ws_id returned by `spawn_workstream` / `spawn_batch` is a
 invent ws_ids — a model that hallucinates `"child-1"` or `"ws-abc"`
 hits the tenant guard in `CoordinatorClient._is_own_subtree`, which
 validates ws_id against `parent_ws_id=coord_ws_id` AND
-`user_id=owner` in storage.  The rejection shape varies by tool:
+`user_id=owner` in storage.  The rejection shape is uniform and
+recovery-oriented:
 
 - **Mutating ops** (`send_to_workstream`, `close_workstream`,
-  `cancel_workstream`, `delete_workstream`) return
-  `{"error": "workstream not in coordinator subtree: <ws_id>", "status": 404}`
-  — the skill should treat this as a tool error, not an empty result.
-- **`inspect_workstream`** returns `{"error": "workstream not found", "ws_id": "<ws_id>"}`
-  (same shape as a genuinely missing row, so the guard can't be
-  used as an existence oracle).
-- **`wait_for_workstream`** reports the offending id with
-  `state="denied"` in its `results` dict; `mode="any"` won't
-  satisfy on a pure-denied list, so a hallucinated id won't trick
-  the wait into reporting "complete".
+  `cancel_workstream`, `delete_workstream`) and
+  **`inspect_workstream`** return
+  `{"error": "no workstream matching '<ref>' among your children; …",
+  "status": 404, "ws_id": "<ref>", "did_you_mean": [...],
+  "children": [...], "children_truncated": bool}` — a did-you-mean
+  (edit distance ≤ 3 against the coord's own children, which catches
+  the garbled-hex incident class: a 32-char id whose `aaa` run
+  collapsed to `a`) plus a roster of the coord's children.  A ref
+  that matches a child's display NAME is called out explicitly with
+  the right id (names are mutable labels, not addresses).  Foreign
+  and nonexistent ids produce the same payload (no existence
+  oracle), every hint references only the coord's own children, and
+  near-miss ids are never auto-resolved — the skill should fix the
+  id and re-issue, not treat the child as dead.
+- **`wait_for_workstream`** validates ids before waiting: a
+  malformed id fails the whole call immediately (`invalid_ws_ids`
+  carries the per-id payloads above, `elapsed=0`); a well-formed id
+  that is foreign, nonexistent, or hard-deleted mid-wait surfaces as
+  `state="not_found"` and aborts the wait on that tick with
+  top-level `error` / `not_found` / `children` fields.
+  `complete=true` therefore means every polled lane really finished
+  — an unobservable id can neither burn the timeout nor ride along
+  to a "complete" result.
 
 Pattern: capture each spawn result in the next tool call's input.
 The JSON tool-result carries `{"child_ws_id": "...", "name": "...",
@@ -337,7 +351,7 @@ persona drift without a real LLM in the loop.
   `spawn_batch` and `close_all_children` use, so your skill can
   parse results / denied arrays correctly.
 - [governance.md](governance.md) — the broader governance surface
-  (`/trust`, `/restrict`, `/stop_cascade`, role-based permissions)
+  (`/trust`, `/restrict`, role-based permissions)
   that wraps every coord session.
 - [settings.md](settings.md) — `coordinator.model_alias` and
   `coordinator.reasoning_effort` settings that gate which LLM runs

docs/docker.md

@@ -59,9 +59,11 @@ is gone. Everything goes through `https://localhost:8443`.
 
 ## Join a bare-metal host
 
-PostgreSQL is published on `127.0.0.1:5432`, so a `turnstone-server` running
-directly on the same machine — for example to use a local GPU — can join the
-same cluster and show up in the console alongside the containerized nodes.
+PostgreSQL, the console's ACME endpoint (`:8090`), and SearxNG (`:8081`) are
+published on `127.0.0.1`, so a `turnstone-server` running directly on the same
+machine — for example to use a local GPU — can join the same cluster (enrolling
+its mTLS cert and running `web_search`) and show up in the console alongside the
+containerized nodes.
 
 Put the secret and connection settings in `~/.config/turnstone/config.toml`
 (secrets belong in this file, not the process environment — keep it `0600`,
@@ -85,18 +87,31 @@ command line:
 
 ```bash
 chmod 600 ~/.config/turnstone/config.toml
-TURNSTONE_NODE_ID=host-1 TURNSTONE_ADVERTISE_URL=http://host.docker.internal:8080 \
+TURNSTONE_NODE_ID=host-1 \
+  TURNSTONE_ADVERTISE_URL=http://host.docker.internal:8080 \
+  TURNSTONE_CONSOLE_URL=http://localhost:8090 \
+  TURNSTONE_SEARXNG_URL=http://localhost:8081 \
   turnstone-server --host 0.0.0.0 --port 8080
 ```
 
 The host server registers itself in PostgreSQL; the console reaches it back via
-`host.docker.internal`. The `jwt_secret` and DB credentials above are the
-dev-stack defaults — match whatever you set in `.env` if you changed them. To
-let a **different** machine join, start the stack with `POSTGRES_BIND=0.0.0.0`
-and use the host's routable IP in the `url` and `TURNSTONE_ADVERTISE_URL` —
-but **set a strong `POSTGRES_PASSWORD` first**, or you'll expose a database with
-the insecure default password (and every user account + API-token hash in it) to
-your network.
+`host.docker.internal`. `TURNSTONE_CONSOLE_URL` points the node at the console's
+published ACME endpoint so it can enroll its mTLS certificate (needed only when
+the cluster runs mTLS; harmless otherwise), and `TURNSTONE_SEARXNG_URL` points
+`web_search` at the published SearxNG. The `jwt_secret` and DB credentials above
+are the dev-stack defaults — match whatever you set in `.env` if you changed them.
+
+To let a server on a **different** machine join, start the stack with
+`TURNSTONE_HOST_IP=<this host's LAN IP>` — that binds PostgreSQL, the console
+ACME endpoint, and SearxNG to that interface. Then on the remote box set the
+three URLs above to that IP, and set `TURNSTONE_ADVERTISE_URL` to the **remote**
+box's own IP (the address the console dials back). **Set a strong
+`POSTGRES_PASSWORD` first** — `TURNSTONE_HOST_IP` exposes the database (and every
+user account + API-token hash in it), the console API, and the unauthenticated
+SearxNG to your network.
+
+To run the bare-metal node as a hardened, persistent service instead of by hand,
+use the systemd units in [`deploy/systemd/`](../deploy/systemd/).
 
 ## Production stack
 
@@ -110,7 +125,7 @@ docker compose -f turnstone/deploy/compose.yaml up
 It's the same shape as the dev stack — Caddy-fronted console, channel, and a
 PostgreSQL all share one database so the console discovers the node — but it
 pulls released images, runs a single server node, and has **no baked-in
-secrets**. Set these in `.env` first (`turnstone-bootstrap` generates them):
+secrets**. Set these in `.env` first (generate with `openssl rand -hex 32`):
 
 ```bash
 TURNSTONE_JWT_SECRET=<python -c "import secrets; print(secrets.token_hex(32))">
@@ -174,15 +189,18 @@ overrides.
 ### Ports
 
 Both stacks publish Caddy (dashboard) and PostgreSQL; the dev stack additionally
-publishes the SearxNG UI on localhost. Everything else is reached through Caddy or
-proxied by the console:
+publishes the console's ACME endpoint and SearxNG on localhost so a bare-metal
+node can enroll its cert and run `web_search`. Everything else is reached through
+Caddy or proxied by the console:
 
 | Variable | Default | Description |
 |----------|---------|-------------|
 | `CONSOLE_HTTPS_PORT` | `8443` | Host port for Caddy (dashboard HTTPS) |
 | `SEARXNG_HTTPS_PORT` | `8444` | Host port for the SearxNG UI via Caddy (dev: localhost-only; prod: opt-in) |
 | `POSTGRES_PORT` | `5432` | Host port for PostgreSQL (for bare-metal joins) |
-| `POSTGRES_BIND` | `127.0.0.1` | Interface PostgreSQL binds on; set `0.0.0.0` for LAN access |
+| `SEARXNG_API_PORT` | `8081` | Host port for the SearxNG API a bare-metal node's `web_search` dials (dev stack) |
+| `TURNSTONE_HOST_IP` | `127.0.0.1` | Interface PostgreSQL, the console ACME endpoint, and SearxNG bind on (dev stack). Set to this host's LAN IP so a bare-metal node on **another machine** can reach them — set a strong `POSTGRES_PASSWORD` first (it also exposes the DB and the unauthenticated SearxNG to your network). |
+| `POSTGRES_BIND` | `127.0.0.1` | Production stack (`turnstone/deploy/compose.yaml`) only: interface PostgreSQL binds on; set to the host's LAN IP for remote joins. |
 
 ### Channel gateway
 
@@ -242,7 +260,7 @@ interface, or anyone who can reach it can search through your instance.
 
 Both stacks install all entry points into a single image (`turnstone`,
 `turnstone-server`, `turnstone-console`, `turnstone-channel`, `turnstone-admin`,
-`turnstone-eval`, `turnstone-bootstrap`):
+`turnstone-eval`, `turnstone-doctor`):
 
 ```bash
 docker compose build            # build the dev image

docs/judge.md

@@ -40,7 +40,7 @@ api_key = ""
 smart_approvals = false       # auto-approve high-confidence "approve" LLM verdicts (opt-in)
 confidence_threshold = 0.95   # Smart Approvals auto-approve bar (LLM recommendation=approve)
 max_context_ratio = 0.5       # max % of judge context window for history
-timeout = 60.0                # seconds (generous for local models)
+timeout = 120.0               # seconds (generous for local models)
 read_only_tools = true        # judge can use read_file/list_directory
 cancel_on_approval = false    # stop judging remaining tool calls once user decides
 ```
@@ -71,7 +71,7 @@ All fields are optional. The judge is enabled by default; use `enabled = false`
 --judge / --no-judge           Enable/disable (default: enabled)
 --judge-model MODEL            Model for judge
 --judge-provider PROVIDER      Provider for judge
---judge-timeout SECONDS        LLM judge timeout (default: 60)
+--judge-timeout SECONDS        LLM judge timeout (default: 120)
 --judge-confidence FLOAT       Confidence threshold, 0-1 (default: 0.95)
 ```
 
@@ -193,9 +193,10 @@ Security hardening blocks access to sensitive paths:
 
 ### Timeout
 
-The `timeout` setting (default 60 seconds) is a total budget across all judge
-turns. Time is decremented after each LLM call. If the budget expires mid-turn,
-the judge attempts to parse whatever partial response is available.
+The `timeout` setting (default 120 seconds) applies **per turn**, not as a total
+budget across turns — each of the up to 5 turns gets a fresh budget, so a slow
+earlier turn doesn't starve later ones. If a turn's budget expires, the judge
+attempts to parse whatever partial response is available.
 
 ---
 
@@ -231,6 +232,23 @@ calls for approval, it calls `_evaluate_intent()` which:
 4. Attaches each heuristic verdict to its item as `_heuristic_verdict`
 5. The daemon thread runs the LLM judge and delivers results via `ui.on_intent_verdict()`
 
+The daemon evaluates items sequentially, so a large parallel batch can outlive
+its approval gate. With `cancel_on_approval = false` (the default) the daemon
+runs every item to completion: verdicts that land after the operator decided
+still stream to the UI and persist, stamped with the decision. The daemon is
+aborted only when the next tool batch supersedes it or the session closes —
+then each unfinished item degrades to an `llm_fallback` verdict. With
+`cancel_on_approval = true` the abort additionally fires the moment the gate
+resolves, trading verdict completeness for inference savings — recommended
+when the judge shares a single local inference backend with the session model,
+where a large batch's remaining judge calls would otherwise compete with the
+next turn's completion.
+
+Verdicts that arrive after a *newer batch* has replaced the judge generation
+are withheld from the live surfaces (a reused call_id must never ride a stale
+`approve` into Smart Approvals) but still persist with
+`user_decision = "superseded"` so the audit trail records the judge's answer.
+
 Sub-agents (plan agent, task agent) are exempt from intent validation -- they
 always get full tool visibility without judge evaluation.
 
@@ -242,7 +260,13 @@ All verdicts are persisted to the `intent_verdicts` table (migration 012):
 
 - Heuristic verdicts are stored when the `approve_request` event is emitted
 - LLM verdicts are stored when the `intent_verdict` event is delivered
-- The `user_decision` column is updated when the user approves or denies
+- The `user_decision` column is updated when the user approves or denies;
+  auto-approved rows carry the bypass reason (`policy`, `blanket`,
+  `auto_approve_tools`, `smart_approval`), and rows whose verdict landed only
+  after a newer batch replaced the judge generation carry `superseded`
+- Every stored verdict — including the benign `risk_level = "none"` majority —
+  is re-attached to its tool call on history replay, so a reloaded workstream
+  shows the same verdict badges the live stream did
 
 The console admin panel exposes verdict history via:
 

docs/memory.md

@@ -26,15 +26,40 @@ Each memory has three dimensions:
 
 ### Memory scopes
 
-| Scope        | Visibility                                                |
-|--------------|-----------------------------------------------------------|
-| `global`     | Visible to all workstreams and users                      |
-| `workstream` | Visible only within the originating workstream            |
-| `user`       | Follows the authenticated user across workstreams         |
+| Scope         | Visibility                                                      |
+|---------------|-----------------------------------------------------------------|
+| `global`      | Visible to all workstreams and users                            |
+| `workstream`  | Visible only within the originating workstream                  |
+| `user`        | Follows the authenticated user across workstreams               |
+| `coordinator` | Coordinator sessions only; follows the user across coordinators |
 
 A memory's identity is the tuple `(name, scope, scope_id)`. Saving a memory
 with the same identity upserts -- updating content while preserving the ID.
 
+### Coordinator scope
+
+Coordinator sessions are isolated to a single scope: `coordinator`, keyed by
+the coordinator's creator `user_id`. It is durable -- every coordinator
+session the same user runs (including concurrent ones) shares one
+orchestration namespace, so procedures and lessons survive close/reopen.
+
+Isolation is bidirectional and enforced by session kind, not by secrecy of
+the scope id:
+
+- A coordinator session can read and write **only** `coordinator`-scope rows.
+  It never sees `global`/`workstream`/`user` memories, so content written by
+  interactive sessions (which routinely ingest untrusted MCP/attachment
+  output) cannot reach a coordinator's system message.
+- Interactive sessions -- including a coordinator's own children, which share
+  its `user_id` -- are rejected from the `coordinator` scope on every memory
+  action. Children cannot plant rows the parent coordinator would read.
+- The REST memory API (`/v1/api/memories`) does not accept the `coordinator`
+  scope at all; the scope is written exclusively through a coordinator
+  session's own memory tool.
+
+Coordinator sessions require an authenticated user identity -- an anonymous
+coordinator cannot be constructed, so the scope id is always a real user.
+
 ### BM25 relevance injection
 
 On every conversation turn, the system:

docs/pgbouncer.md

@@ -108,7 +108,7 @@ pgbouncer:
   maxClientConn: 5000
   maxDbConnections: 80
 ```
-:
+
 ---
 
 ## Configuration reference

docs/releasing.md

@@ -6,10 +6,9 @@ Turnstone ships several parallel release tracks from a single PyPI package.
 
 | Track | Versions | Branch | Docker tags | PyPI install |
 |-------|----------|--------|-------------|--------------|
-| **Legacy 1.0** | `1.0.x` | `stable/1.0` | `:1.0.x`, `:1.0` | `pip install 'turnstone==1.0.*'` |
-| **Stable 1.3** | `1.3.x` | `stable/1.3` | `:1.3.x`, `:1.3` | `pip install 'turnstone==1.3.*'` |
-| **Stable 1.4** | `1.4.x` | `stable/1.4` | `:1.4.x`, `:1.4`, `:stable`, `:latest` | `pip install turnstone` |
-| **Experimental** | `1.5.0aN` | `main` | `:1.5.0aN`, `:experimental` | `pip install turnstone --pre` |
+| **Stable 1.5** | `1.5.x` | `stable/1.5` | `:1.5.x`, `:1.5` | `pip install 'turnstone==1.5.*'` |
+| **Stable 1.6** | `1.6.x` | `stable/1.6` | `:1.6.x`, `:1.6`, `:stable`, `:latest` | `pip install turnstone` |
+| **Experimental** | `1.7.0aN` | `main` | `:1.7.0aN`, `:experimental` | `pip install turnstone --pre` |
 
 - **Stable** tracks receive bugfixes only.  The most-recent stable minor
   owns the `:stable` / `:latest` Docker tags and the default PyPI
@@ -17,8 +16,10 @@ Turnstone ships several parallel release tracks from a single PyPI package.
 - **Experimental** (always on `main`) receives new features. May be
   rough around the edges.
 - When experimental matures, it is promoted to a new stable minor via
-  a `stable/X.Y` branch; older stable branches continue to receive
-  security fixes until explicitly retired.
+  a `stable/X.Y` branch. One prior stable track is maintained alongside
+  the current one; at each promotion the oldest track is retired — its
+  branch is deleted, while its tags and released artifacts remain
+  available.
 
 ## Version Scheme
 
@@ -33,17 +34,17 @@ Turnstone ships several parallel release tracks from a single PyPI package.
 ## Releasing an Experimental Version (from main)
 
 ```bash
-scripts/release.sh 1.5.0a2 --push
+scripts/release.sh 1.7.0a2 --push
 ```
 
-This bumps `pyproject.toml` + `turnstone/__init__.py`, regenerates `uv.lock`, commits, tags `v1.5.0a2`, and pushes. CI runs, then publish + Docker workflows fire automatically.
+This bumps `pyproject.toml` + `turnstone/__init__.py`, regenerates `uv.lock`, commits, tags `v1.7.0a2`, and pushes. CI runs, then publish + Docker workflows fire automatically.
 
 ## Releasing a Stable Patch (from stable/X.Y)
 
 ```bash
-git checkout stable/1.4
+git checkout stable/1.6
 git cherry-pick <commit-hash>    # bugfix from main
-scripts/release.sh 1.4.1 --push
+scripts/release.sh 1.6.1 --push
 ```
 
 ## Promoting Experimental to Stable
@@ -52,19 +53,19 @@ When `main` is ready for a stable release:
 
 ```bash
 # 1. Tag the stable release on main
-scripts/release.sh 1.5.0 --push
+scripts/release.sh 1.6.0 --push
 
 # 2. Create the stable maintenance branch from that tag
-git branch stable/1.5 v1.5.0
-git push origin stable/1.5
+git branch stable/1.6 v1.6.0
+git push origin stable/1.6
 
 # 3. Start the next experimental cycle on main
-scripts/release.sh 1.6.0a1 --push
+scripts/release.sh 1.7.0a1 --push
 ```
 
-The previous stable branch (`stable/1.4`) continues to receive
-security-only patches; older tracks (`stable/1.0`, `stable/1.3`) are
-retired when they fall out of support.
+The previous stable branch continues to receive security-only patches;
+the track before it is retired at each promotion (at 1.6.0:
+`stable/1.5` stays maintained, `stable/1.4` is retired).
 
 ## CI/CD Pipeline
 

docs/tls.md

@@ -88,6 +88,32 @@ Console (CA + ACME Server)
 - **Frontend cert** (HTTPS): From an external ACME CA (e.g. Let's Encrypt)
   if `tls.acme_directory` is set, otherwise self-issued from the internal CA.
 
+### Boot, retry, and fallback
+
+With `tls.enabled`, a node fetches the CA cert and requests its own cert
+during startup, retrying with exponential backoff (6 attempts, ~31 s total)
+— enough to absorb a whole-stack restart where every node races the console
+for its listener. If all attempts fail, the node **falls back to plain
+HTTP** (availability over confidentiality) and reports `"tls": "fallback"`
+in `GET /health`; a node serving HTTPS reports `"tls": "active"`, and the
+key is absent when TLS is disabled. Fallback persists until the next
+restart — it is not upgraded in place.
+
+### Container healthcheck under mTLS
+
+An mTLS listener rejects plain-HTTP probes at the socket, so
+`docker/healthcheck.py` falls back to HTTPS when the plain probe fails:
+it presents the node's own cert as the client cert and pins the cluster
+CA, using the PEM files the server writes at boot under
+`$TURNSTONE_TLS_PEM_DIR` (default `<tmpdir>/turnstone-tls`). The probe
+dials `localhost` for the TLS attempt — the internal CA issues DNS SANs
+only, so a literal-IP URL would fail verification. Cert renewal rewrites
+the PEM dir alongside the live listener swap, so the probe's client cert
+never outlives the served cert. With TLS disabled the plain probe succeeds
+and the PEM directory is never consulted. On bare metal with multiple
+nodes per host, set `TURNSTONE_TLS_PEM_DIR` per node (each boot clears
+stale `lacme-pem-*` dirs under its root).
+
 ---
 
 ## Configuration
@@ -218,7 +244,10 @@ const client = new TurnstoneServer({
 ### Node Bootstrap Flow
 
 1. Node starts, connects to shared database (plain connection)
-2. Discovers console URL from `services` table
+2. Discovers the console URL from the `services` table — or honors an explicit
+   `TURNSTONE_CONSOLE_URL` (a bare-metal node outside the compose network can't
+   resolve the in-cluster `console` name, so it points this at the console's
+   published ACME endpoint)
 3. Fetches CA root cert from `http://console/acme/ca.pem` (plain HTTP, TOFU)
 4. Requests a service cert via ACME (plain HTTP, JWS-signed). The cert's
    primary domain / SAN is the node's **advertised host** (the host of
@@ -265,7 +294,8 @@ cert's SANs don't include the dialed name.
 
 The console registers itself in the `services` table on startup. If the console
 hasn't started or the registration expired (1 hour TTL), nodes can't discover
-it. Use `--console-url` explicitly.
+it. Set `TURNSTONE_CONSOLE_URL` to a reachable console address (this is also how
+a bare-metal node that can't resolve the in-cluster `console` name enrolls).
 
 ### Browser HTTPS to the console
 

examples/door-game/.gitignore

@@ -0,0 +1,9 @@
+__pycache__/
+.venv/
+*.db
+*.db-wal
+*.db-shm
+.ruff_cache/
+.pytest_cache/
+.mypy_cache/
+uv.lock

examples/door-game/README.md

@@ -0,0 +1,282 @@
+# Understone
+
+A small, multiplayer, BBS-style **ANSI door game** served over the Model
+Context Protocol (MCP). It is a text RPG in the spirit of *Legend of the Red
+Dragon* — explore an overworld of box-drawing maps, fight wandering monsters,
+shop and rest in town, and descend a dungeon — except the "door" is an MCP
+server and the player drives it by talking to an AI assistant.
+
+The server is the rules engine and the single source of truth. Players share
+**one persistent world**: your assistant calls tools, the server returns
+authoritative frames and facts, and the assistant narrates the story around
+them.
+
+This is a self-contained reference example. It depends only on `mcp` — there
+is no dependency on Turnstone itself — so it runs against any MCP client.
+
+## How to play
+
+There is **no prompt to paste and no persona to configure**. The tool schema
+is the whole interface. Once the server is registered with your assistant:
+
+1. Tell your assistant you'd like to play an ANSI door game / text dungeon
+   RPG (it can discover the tools by name and description).
+2. The assistant calls `door_help` to learn how to run the world, then
+   `door_join` with your adventurer's name.
+3. Play unfolds as a conversation: "head east", "fight it", "rest at the inn".
+
+Everything the assistant needs to run the game well is returned by
+`door_help`.
+
+## Gameplay
+
+A run is a little RPG loop, played a bit each day:
+
+- **Explore** the overworld of box-drawing maps. Walking is free, but the wild
+  country has texture — a step may turn up a wandering monster, a purse of
+  gold, a healing spring, a small trap (which can never kill you), or a scrap
+  of old Vale lore. Only one such find happens per move, and the non-combat
+  ones don't interrupt your walk.
+- **Fight, shop, and heal** in and around town. Fighting and descending one
+  rung of the dungeon each spend one of your daily turns; resting, shopping and
+  moving do not.
+- **Delve the deep, a rung at a time.** The dungeon is a ladder of guardians:
+  each `descend` faces the next one past your deepest and either advances your
+  depth or bounces you home (your depth persists either way). Carry a few
+  **potions in your satchel** — `quaff` the strongest when you choose, and if a
+  fight would kill you the satchel saves you automatically, the elixir burning
+  down your throat at death's edge. Clearing a rung also yields **forge ore**,
+  which rides the satchel (a won forest fight sometimes turns up a little, too).
+- **Forge an edge — with gold AND ore.** At the shop's **forge** you can add a
+  +1 edge to your equipped weapon or armour, up to a cap, each step dearer than
+  the last. A step costs gold *and* the ore you won in the deep — so the forge is
+  fed by descending, not just by a fat purse. Watch, too, for the **rare beasts**
+  that prowl the forest: felling one is Herald news and always drops a draught.
+- **Win the game** by slaying **the Wyrm Below**. Once your hero is seasoned
+  enough AND has plumbed the deep to its floor, `challenge` it at the dungeon. A
+  victory frees the Vale, carves your run into the **Hall of Legends**, and — in
+  the tradition of the classic BBS door games — begins a new life: your
+  character resets to first-day gear and stats but keeps a permanent ★ for every
+  Wyrm slain, ready to do it all again.
+- **Read the news.** `door_log` is the **Understone Herald**, a shared
+  broadsheet of notable deeds across the whole world — who joined, who rose a
+  level, who was dragged home by a goblin, and who freed the Vale.
+- **Make it social.** It is a shared world, so you can touch other players.
+  `ambush` a rival who has not yet acted today — a classic
+  style player-kill that robs a sleeping foe of some gold, except the surest
+  defence is simply to take your own turn (an active player is awake and can't
+  be caught). Lose the ambush and *you* are the one who flees, shamed on the
+  feed. `post` a private note another player reads on their next visit (it
+  never reaches the public Herald). Or `gamble` a little gold at the inn's dice
+  against the house. Ambush spends a turn; mail and dice do not.
+- **Bank your coin.** The inn keeps a strongbox: `deposit` gold into the
+  **vault** and `withdraw` it later (no turn either way). Banked gold is **safe
+  from ambush** — a sleeping-robber only ever lifts what you carry — and it is
+  the one thing that **survives a Wyrm-win reset**, carrying wealth across runs.
+
+## Installation
+
+This example uses [`uv`](https://docs.astral.sh/uv/). From the example
+directory:
+
+```bash
+cd examples/door-game
+uv venv
+uv pip install -e .
+```
+
+That installs the `understone` entry point into the environment.
+
+To run the tests and quality gates:
+
+```bash
+uv pip install -e ".[test,dev]"
+uv run pytest
+uv run ruff check .
+uv run ruff format --check .
+uv run mypy understone/
+```
+
+## Running the server
+
+By default the server speaks the **stdio** transport, which is how MCP clients
+launch a per-session subprocess:
+
+```bash
+understone
+```
+
+To host one shared world over HTTP for several clients, run the
+**streamable-http** transport as a single long-lived process:
+
+```bash
+UNDERSTONE_TRANSPORT=streamable-http understone
+```
+
+### Environment variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `UNDERSTONE_DB` | `./understone.db` | SQLite database file for the world's state. |
+| `UNDERSTONE_WORLD` | _(packaged pack)_ | Directory of a content pack to load instead of the bundled Vale of Understone. |
+| `UNDERSTONE_TRANSPORT` | `stdio` | `stdio` or `streamable-http`. |
+| `UNDERSTONE_HOST` | `127.0.0.1` | Bind host (streamable-http only). |
+| `UNDERSTONE_PORT` | `8077` | Bind port (streamable-http only). |
+| `UNDERSTONE_PATH` | `/mcp` | HTTP path for the MCP endpoint (streamable-http only). |
+
+## The Watch — a live spectator view
+
+When the server runs under the **streamable-http** transport, it also serves a
+read-only **Watch** page: the lobby TV of the Vale. Point a browser at
+
+```
+http://127.0.0.1:8077/watch
+```
+
+(the host and port follow `UNDERSTONE_HOST` / `UNDERSTONE_PORT`). It is a
+period **CRT spectator console** — a green-and-amber phosphor map of the whole
+world with every adventurer's `☻` marker, a live **Understone Herald** feed, the
+**Hall of Legends**, and a roster of who is currently abroad. It refreshes every
+couple of seconds; if it loses contact it dims and reads `SIGNAL LOST` until the
+server returns. The console's palette follows the pack: a world may pick its own
+CRT colour with `settings.watch_theme` (`phosphor` green, `amber` gold, `ice`
+blue, `ember` red), defaulting to the Vale's green if it says nothing.
+
+The Watch is **strictly read-only**. Input never flows through it — there are no
+controls, no forms, nothing that can change the world. It reads the same shared
+state the tools do and paints it; that is all. There is no authentication, in
+keeping with the rest of this easter-egg server (see the safety note below), so
+treat the page as you would the MCP endpoint itself.
+
+> _Screenshot: the Watch console — a phosphor-green overworld map with amber
+> `☻` markers, the Herald feed and Hall of Legends down the right-hand rail.
+> (Image placeholder; run the server and open the URL to see it live.)_
+
+When the Watch is up, the `door_join` welcome and the `door_help` manual both
+print its URL so players (and the assistant narrating for them) know it exists.
+If you bind to `0.0.0.0` to share the world across a network, advertise a host
+that browsers can actually reach (your machine's LAN address or hostname) rather
+than `0.0.0.0` itself — the link is composed from `UNDERSTONE_HOST`.
+
+## Authoring worlds
+
+The Vale of Understone is just the *bundled* world. The whole game — its map,
+monsters, economy, and endgame — is a **content pack**: a directory of six JSON
+files the server loads at start. Nothing about the Vale is privileged; point
+the server at another pack and it runs that world instead. This is the seam
+where the game becomes its own authoring target: a pack is plain data, so a
+person *or an LLM* can write one, and the same zero-setup philosophy that makes
+the game playable with no prompt makes it **authorable with no code**.
+
+The loop has these commands:
+
+```bash
+understone newpack mypack        # scaffold a pack (copies the Vale as a template)
+# ...edit or LLM-generate the JSON in mypack/ to describe your world...
+understone validate mypack       # check it; prints a report or names what's wrong
+understone simulate mypack       # play a greedy bot through it and measure the balance
+UNDERSTONE_WORLD=mypack understone   # serve your world
+understone worlds                # list the bundled worlds and whether each is sound
+```
+
+`newpack` writes a starting template plus an `AUTHORING.md` manual — the
+file-by-file schema, the enforced limits, and design guidance — written to be
+followed cold by a model. `validate` loads the pack through exactly the same
+hardened loader the server uses and either prints a summary ending **"This pack
+is sound. The door stands open."** or fails with one precise line naming the
+file, the row, and the field at fault.
+
+`simulate` is the **balance instrument**: it drives a deliberately simple,
+greedy bot through the *real* game — the same `join`/`move`/`action` calls the
+tools make — over a seeded RNG and an injected clock, then prints a report
+(final level, gold earned, fights fought, rungs cleared, whether and when the
+Wyrm fell). It is a tuning probe, not a player to admire: it answers "is this
+world *shaped* right, and is it *winnable*?". Pass `--days N`, `--seed S`, or
+`--seeds K` for a multi-seed sweep with means and spreads. `worlds` lists every
+bundled world — the default Vale plus any alternate packs shipped under
+`understone/world/packs/` — loading each so it can report it as sound or flawed.
+
+**A second bundled world: The Cinder Wastes.** Understone ships a second world
+alongside the Vale, in `understone/world/packs/cinder-wastes/` — a volcanic
+ash-and-slag map whose Watch page glows ember-red instead of the Vale's green
+phosphor. It is the pipeline's own dogfood: it was authored **by an LLM working
+only from `AUTHORING.md` and the `validate` loop**, with no engine code touched,
+then bundled verbatim. `understone worlds` lists it as sound, and
+`understone simulate understone/world/packs/cinder-wastes --days 50 --seeds 3`
+shows the greedy bot taking its Magma Wyrm — the end-to-end proof that a world
+described purely as data, from the manual alone, is genuinely playable to
+victory. Serve it with
+`UNDERSTONE_WORLD=understone/world/packs/cinder-wastes understone`.
+
+Packs are validated **hard** at load: every map glyph must render as exactly
+one terminal column (no fullwidth runes, no emoji, no combining marks — the
+frames are box-drawing rectangles) and may not collide with the frame's
+box-drawing lines or the player markers, dimensions and counts are bounded,
+display names are length-checked, and every cross-reference (a legend
+character, a starting item, the boss monster, a dungeon tier) must resolve. The
+loader also pins the rules that keep the endgame coherent: a world has exactly
+one boss, and a dungeon tier's lead monster (its fixed rung guardian) may not be
+a rare. Because packs are now routinely untrusted, generated output, those error
+messages are not a nuisance — they are the **feedback loop**. Iterate against
+them until the door stands open.
+
+## Registering with Turnstone
+
+Understone is an ordinary MCP server, so it plugs into Turnstone's MCP client
+config two ways.
+
+**Stdio (per-session subprocess).** Turnstone launches the `understone`
+command for each session. Each session gets its own subprocess, so for a
+truly shared world prefer the HTTP form below; stdio is simplest for solo
+play.
+
+```toml
+[mcp.servers.understone]
+command = "understone"
+
+[mcp.servers.understone.env]
+UNDERSTONE_DB = "/var/lib/understone/world.db"
+```
+
+**Streamable-HTTP (one shared world).** Run a single Understone process with
+`UNDERSTONE_TRANSPORT=streamable-http` and point every client at its URL. This
+is the right setup for multiplayer: one process, one database, one world that
+all adventurers share.
+
+```toml
+[mcp.servers.understone]
+url = "http://localhost:8077/mcp"
+```
+
+> **Operator note.** For multiplayer, start exactly one shared process —
+> `UNDERSTONE_TRANSPORT=streamable-http understone` — and have all clients use
+> the url form. The world lives in a single SQLite file written by that one
+> process.
+
+## The tools
+
+| Tool | What it does |
+|------|--------------|
+| `door_help` | The game-master manual. Start here. |
+| `door_join` | Create or resume an adventurer; returns the opening map. |
+| `door_status` | The character sheet (read-only). |
+| `door_look` | Redraw the current view — overworld map or location menu. |
+| `door_move` | Walk the overworld (free; no daily turn spent). |
+| `door_action` | Context verbs: fight, flee, ambush (a rival), rest, deposit/withdraw (the inn vault), buy, sell, forge (a +1 edge, gold + ore), heal, gamble (inn dice), descend (one rung), challenge (the Wyrm), post (mail another player), quaff (a carried potion), leave. |
+| `door_log` | The Understone Herald — the shared feed of notable deeds. |
+| `door_rank` | The leaderboard, plus the Hall of Legends (★ marks Wyrm kills). |
+| `door_bestow` | Game-master grant of a little gold/healing for a story beat. |
+
+## A note on identity and safety
+
+This example is an **easter egg**, not a hardened service. Identity is
+**self-asserted**: a "player" is just a name passed to the tools, and there is
+**no authentication** — anyone who can reach the server can act as any name.
+That is fine for a shared toy world among people who trust each other, and
+deliberately out of scope for a game. Do not store anything sensitive in it,
+and if you expose the HTTP transport beyond localhost, put it behind whatever
+access control your environment already provides.
+
+The game master's `door_bestow` channel can only grant small, capped amounts
+of in-game gold and healing — never items, never turns — and every grant is
+written to the public in-world log, so its reach is bounded by design.

examples/door-game/pyproject.toml

@@ -0,0 +1,55 @@
+[build-system]
+requires = ["hatchling>=1.29"]
+build-backend = "hatchling.build"
+
+[project]
+name = "understone"
+version = "0.10.0"
+description = "Understone — a BBS-style ANSI door game served over MCP."
+requires-python = ">=3.11"
+license = "Apache-2.0"
+dependencies = [
+    "mcp>=1.27,<2",
+]
+
+[project.scripts]
+understone = "understone.server:main"
+
+[project.optional-dependencies]
+test = ["pytest>=9.0"]
+dev = ["ruff>=0.9", "mypy>=1.14"]
+
+[tool.hatch.build.targets.wheel]
+packages = ["understone"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+
+[tool.ruff]
+target-version = "py311"
+line-length = 100
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I", "N", "UP", "B", "A", "SIM", "TCH"]
+ignore = ["E501"]
+
+[tool.ruff.format]
+quote-style = "double"
+
+[tool.mypy]
+python_version = "3.11"
+strict = true
+warn_return_any = true
+warn_unused_configs = true
+disallow_untyped_defs = true
+disallow_incomplete_defs = true
+check_untyped_defs = true
+no_implicit_optional = true
+
+[[tool.mypy.overrides]]
+module = ["mcp", "mcp.*"]
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "tests.*"
+disallow_untyped_defs = false

examples/door-game/tests/conftest.py

@@ -0,0 +1,256 @@
+"""Shared test fixtures and builders.
+
+These builders construct engine objects directly (no JSON loader) so the
+engine tests stay independent of the content pack. Later chunks add
+fixtures that load the shipped world and build the game façade.
+"""
+
+from __future__ import annotations
+
+from collections import Counter
+from datetime import UTC, datetime
+from typing import TYPE_CHECKING
+
+import pytest
+
+from understone.engine.models import (
+    Item,
+    LocationDef,
+    Mode,
+    Monster,
+    Player,
+    Settings,
+    Slot,
+    TerrainDef,
+    WorldEvent,
+    Zone,
+)
+from understone.engine.world import World
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+    from understone.game import Game
+
+# ---------------------------------------------------------------------------
+# Terrain kinds for synthetic test worlds
+# ---------------------------------------------------------------------------
+
+GRASS = TerrainDef(key="grass", glyph=".", walkable=True, encounter_rate=0.0, color="floor")
+WALL = TerrainDef(key="wall", glyph="█", walkable=False, encounter_rate=0.0, color="wall")
+WATER = TerrainDef(key="water", glyph="~", walkable=False, encounter_rate=0.0, color="water")
+FOREST = TerrainDef(key="forest", glyph="↑", walkable=True, encounter_rate=1.0, color="tree")
+SAFE_FOREST = TerrainDef(key="forest", glyph="↑", walkable=True, encounter_rate=0.0, color="tree")
+
+
+DEFAULT_SETTINGS = Settings(
+    daily_turns=10,
+    rest_cost=15,
+    heal_cost_per_hp=2,
+    starting_gold=20,
+    starting_weapon="rusty_dagger",
+    starting_armor="cloth_tunic",
+    start_hp=20,
+    start_atk=3,
+    start_def=0,
+    xp_base=100,
+    growth_max_hp=6,
+    growth_atk=2,
+    growth_def=1,
+    bestow_daily_budget=25,
+    dungeon_tiers=(4, 5),
+    boss_monster="wyrm_below",
+    wyrm_min_level=6,
+    ambush_min_level=3,
+    ambush_level_band=2,
+    ambush_gold_pct=25,
+    post_daily_cap=5,
+    gamble_max_bet=50,
+    gamble_daily_cap=5,
+    satchel_max=3,
+    forge_base_cost=60,
+    forge_max_plus=3,
+    rare_drop_item="minor_potion",
+    forge_ore_item="iron_ore",
+    forge_ore_per_plus=1,
+    ore_dungeon_drop=2,
+    ore_forest_chance=0.2,
+    watch_theme="phosphor",
+)
+
+
+def make_settings(**overrides: object) -> Settings:
+    """Return DEFAULT_SETTINGS with field overrides for band testing."""
+    base = {
+        "daily_turns": DEFAULT_SETTINGS.daily_turns,
+        "rest_cost": DEFAULT_SETTINGS.rest_cost,
+        "heal_cost_per_hp": DEFAULT_SETTINGS.heal_cost_per_hp,
+        "starting_gold": DEFAULT_SETTINGS.starting_gold,
+        "starting_weapon": DEFAULT_SETTINGS.starting_weapon,
+        "starting_armor": DEFAULT_SETTINGS.starting_armor,
+        "start_hp": DEFAULT_SETTINGS.start_hp,
+        "start_atk": DEFAULT_SETTINGS.start_atk,
+        "start_def": DEFAULT_SETTINGS.start_def,
+        "xp_base": DEFAULT_SETTINGS.xp_base,
+        "growth_max_hp": DEFAULT_SETTINGS.growth_max_hp,
+        "growth_atk": DEFAULT_SETTINGS.growth_atk,
+        "growth_def": DEFAULT_SETTINGS.growth_def,
+        "bestow_daily_budget": DEFAULT_SETTINGS.bestow_daily_budget,
+        "dungeon_tiers": DEFAULT_SETTINGS.dungeon_tiers,
+        "boss_monster": DEFAULT_SETTINGS.boss_monster,
+        "wyrm_min_level": DEFAULT_SETTINGS.wyrm_min_level,
+        "ambush_min_level": DEFAULT_SETTINGS.ambush_min_level,
+        "ambush_level_band": DEFAULT_SETTINGS.ambush_level_band,
+        "ambush_gold_pct": DEFAULT_SETTINGS.ambush_gold_pct,
+        "post_daily_cap": DEFAULT_SETTINGS.post_daily_cap,
+        "gamble_max_bet": DEFAULT_SETTINGS.gamble_max_bet,
+        "gamble_daily_cap": DEFAULT_SETTINGS.gamble_daily_cap,
+        "satchel_max": DEFAULT_SETTINGS.satchel_max,
+        "forge_base_cost": DEFAULT_SETTINGS.forge_base_cost,
+        "forge_max_plus": DEFAULT_SETTINGS.forge_max_plus,
+        "rare_drop_item": DEFAULT_SETTINGS.rare_drop_item,
+        "forge_ore_item": DEFAULT_SETTINGS.forge_ore_item,
+        "forge_ore_per_plus": DEFAULT_SETTINGS.forge_ore_per_plus,
+        "ore_dungeon_drop": DEFAULT_SETTINGS.ore_dungeon_drop,
+        "ore_forest_chance": DEFAULT_SETTINGS.ore_forest_chance,
+        "watch_theme": DEFAULT_SETTINGS.watch_theme,
+    }
+    base.update(overrides)
+    return Settings(**base)  # type: ignore[arg-type]
+
+
+def make_player(**overrides: object) -> Player:
+    """Build a Player at sane defaults; override any field by keyword."""
+    fields = {
+        "name": "Tester",
+        "x": 5,
+        "y": 5,
+        "hp": 20,
+        "max_hp": 20,
+        "level": 1,
+        "xp": 0,
+        "gold": 50,
+        "atk": 5,
+        "def_": 1,
+        "weapon_id": "rusty_dagger",
+        "armor_id": "cloth_tunic",
+        "turns_left": 10,
+        "turn_day": 0,
+        "mode": Mode.TILE,
+        "at_location": "",
+        "created_at": "2026-01-01T00:00:00+00:00",
+        "last_seen": "2026-01-01T00:00:00+00:00",
+        "log_cursor": 0,
+        "bestow_spent": 0,
+        "bestow_day": 0,
+        "wins": 0,
+        "posts_sent": 0,
+        "post_day": 0,
+        "gambles": 0,
+        "gamble_day": 0,
+    }
+    fields.update(overrides)
+    return Player(**fields)  # type: ignore[arg-type]
+
+
+def make_monster(**overrides: object) -> Monster:
+    """Build a Monster at tier-1 defaults."""
+    fields = {
+        "tier": 1,
+        "name": "Field Rat",
+        "hp": 6,
+        "atk": 3,
+        "def_": 0,
+        "xp": 8,
+        "gold": 3,
+        "monster_id": "",
+        "boss": False,
+    }
+    fields.update(overrides)
+    return Monster(**fields)  # type: ignore[arg-type]
+
+
+def make_world(
+    *,
+    grid: list[list[TerrainDef]] | None = None,
+    width: int = 11,
+    height: int = 11,
+    spawn: tuple[int, int] = (5, 5),
+    locations: list[LocationDef] | None = None,
+    zones: list[Zone] | None = None,
+    monsters: list[Monster] | None = None,
+    items: list[Item] | None = None,
+    settings: Settings | None = None,
+    events: list[WorldEvent] | None = None,
+) -> World:
+    """Build a small synthetic World (all-grass by default)."""
+    if grid is None:
+        grid = [[GRASS for _ in range(width)] for _ in range(height)]
+    return World(
+        name="Test Vale",
+        width=width,
+        height=height,
+        spawn=spawn,
+        terrain=grid,
+        locations=locations or [],
+        zones=zones or [],
+        monsters=monsters or [make_monster()],
+        items=items or _default_items(),
+        settings=settings or DEFAULT_SETTINGS,
+        events=events,
+    )
+
+
+def _default_items() -> list[Item]:
+    return [
+        Item("rusty_dagger", "Rusty Dagger", Slot.WEAPON, 2, 0, 0, 0),
+        Item("short_sword", "Short Sword", Slot.WEAPON, 5, 0, 0, 40),
+        Item("cloth_tunic", "Cloth Tunic", Slot.ARMOR, 0, 1, 0, 0),
+        Item("leather_armor", "Leather Armor", Slot.ARMOR, 0, 3, 0, 50),
+        Item("minor_potion", "Minor Potion", Slot.CONSUMABLE, 0, 0, 15, 12),
+        Item("iron_ore", "Iron Ore", Slot.MATERIAL, 0, 0, 0, 0),
+    ]
+
+
+def fixed_clock(moment: datetime) -> Callable[[], datetime]:
+    """Return a clock callable that always reports *moment*."""
+
+    def _clock() -> datetime:
+        return moment
+
+    return _clock
+
+
+def utc(year: int, month: int, day: int, hour: int = 0, minute: int = 0) -> datetime:
+    """Construct a tz-aware UTC datetime."""
+    return datetime(year, month, day, hour, minute, tzinfo=UTC)
+
+
+# ---------------------------------------------------------------------------
+# Satchel test helpers (the v0.10 stack encoding)
+# ---------------------------------------------------------------------------
+# The satchel is stack-based ("id:qty"); these wrap the game façade's stack
+# helpers so a test can seed/read a bag as a flat id list (duplicate ids
+# collapse to one stack), keeping the assertions readable. Shared by the
+# descend and Wyrm suites.
+
+
+def set_satchel(game: Game, player: object, ids: list[str]) -> None:
+    """Seed *player*'s satchel from a flat id list (duplicates -> one stack qty)."""
+    counts = Counter(ids)
+    stacks = [(item_id, counts[item_id]) for item_id in dict.fromkeys(ids)]
+    game._satchel_set_stacks(player, stacks)  # type: ignore[arg-type]
+
+
+def satchel_ids(game: Game, player: object) -> list[str]:
+    """Return the satchel as a flat id list, each stack expanded by its qty."""
+    out: list[str] = []
+    for item_id, qty in game._satchel_stacks(player):  # type: ignore[arg-type]
+        out.extend([item_id] * qty)
+    return out
+
+
+@pytest.fixture
+def small_world() -> World:
+    """An 11x11 all-grass world with the default content tables."""
+    return make_world()

examples/door-game/tests/golden/menu_inn.txt

@@ -0,0 +1,7 @@
+┌── The Sleeping Drake ───┐
+│ A warm hearth crackles. │
+│ A bed costs 15 gold.    │
+│                         │
+│ (R)est  (L)eave         │
+└─────────────────────────┘
+[ status ]

examples/door-game/tests/golden/viewport_edge_nw.txt

@@ -0,0 +1,8 @@
+┌─ Vale ──┐
+│@........│
+│.........│
+│.........│
+│.........│
+│.........│
+└─────────┘
+[ status ]

examples/door-game/tests/golden/viewport_spawn.txt

@@ -0,0 +1,8 @@
+┌─ Vale ──┐
+│.........│
+│.........│
+│....@....│
+│.........│
+│.........│
+└─────────┘
+[ status ]

examples/door-game/tests/test_cli.py

@@ -0,0 +1,374 @@
+"""Tests for the pack-authoring command surface.
+
+Covers the validate/newpack functions directly (sound and broken packs, the
+scaffold round-trip, AUTHORING.md generation from the live loader bands, and
+the refuse-non-empty guard), the ``server.main`` argv dispatch (validate routes
+through and bare invocation still reaches serve without binding a port), and
+one end-to-end subprocess smoke of ``python -m understone validate``.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+import subprocess
+import sys
+from io import StringIO
+from pathlib import Path
+from typing import TYPE_CHECKING, Any
+
+import pytest
+
+from understone import cli, server
+from understone.world import loader
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+EXAMPLE_DIR = Path(__file__).resolve().parents[1]
+SHIPPED = EXAMPLE_DIR / "understone" / "world" / "data"
+
+# The six content files a scaffolded pack must carry, plus the manual.
+_PACK_JSONS = {
+    "terrain.json",
+    "monsters.json",
+    "items.json",
+    "locations.json",
+    "events.json",
+    "world.json",
+}
+
+
+# ---------------------------------------------------------------------------
+# cli_validate
+# ---------------------------------------------------------------------------
+
+
+def test_cli_validate_sound_pack_reports_and_returns_zero() -> None:
+    out, err = StringIO(), StringIO()
+    rc = cli.cli_validate(SHIPPED, out=out, err=err)
+
+    assert rc == 0
+    report = out.getvalue()
+    assert "This pack is sound. The door stands open." in report
+    # The report surfaces the headline facts the brief calls for.
+    assert "The Vale of Understone" in report
+    assert "96x48" in report
+    assert "1 boss" in report
+    assert "% fight" in report
+    assert err.getvalue() == ""
+
+
+def test_cli_validate_broken_pack_names_field_and_returns_two(tmp_path: Path) -> None:
+    # A pack whose daily_turns is out of band: the loader names the field.
+    pack = _clone_shipped(tmp_path)
+    _patch_world(pack, _break_daily_turns)
+
+    out, err = StringIO(), StringIO()
+    rc = cli.cli_validate(pack, out=out, err=err)
+
+    assert rc == 2
+    message = err.getvalue()
+    assert message.startswith("The pack is flawed:")
+    assert "daily_turns" in message  # the offending field is named
+    assert out.getvalue() == ""
+
+
+def test_cli_validate_missing_directory_returns_two(tmp_path: Path) -> None:
+    out, err = StringIO(), StringIO()
+    rc = cli.cli_validate(tmp_path / "nope", out=out, err=err)
+    assert rc == 2
+    assert "The pack is flawed:" in err.getvalue()
+
+
+# ---------------------------------------------------------------------------
+# cli_newpack
+# ---------------------------------------------------------------------------
+
+
+def test_cli_newpack_writes_template_and_manual(tmp_path: Path) -> None:
+    dest = tmp_path / "mypack"
+    out, err = StringIO(), StringIO()
+    rc = cli.cli_newpack(dest, out=out, err=err)
+
+    assert rc == 0
+    present = {p.name for p in dest.iterdir()}
+    assert present >= _PACK_JSONS  # the six content files are all there
+    assert "AUTHORING.md" in present
+    # Next-steps guidance points the author at the validate verb.
+    assert "understone validate" in out.getvalue()
+
+
+def test_cli_newpack_scaffold_validates(tmp_path: Path) -> None:
+    """The load-bearing test: a freshly scaffolded pack loads cleanly.
+
+    newpack -> load_world round-trip. If the template the scaffolder copies
+    ever drifts out of the loader's bands, this fails immediately.
+    """
+    dest = tmp_path / "mypack"
+    assert cli.cli_newpack(dest, out=StringIO(), err=StringIO()) == 0
+
+    world = loader.load_world(dest)
+    assert world.name == "The Vale of Understone"
+    assert world.width == 96
+
+
+def test_cli_newpack_authoring_md_renders_live_band(tmp_path: Path) -> None:
+    """AUTHORING.md's bands are generated from the loader, not hand-copied.
+
+    The daily_turns band is read straight from the live loader table and must
+    appear verbatim in the scaffolded manual — proving generation from source.
+    """
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+    lo, hi = loader.SETTINGS_BANDS["daily_turns"]
+    assert lo is not None and hi is not None
+    assert f"`{lo}..{hi}`" in manual
+    assert "daily_turns" in manual
+
+
+def test_cli_newpack_authoring_md_has_width_rule_and_live_palette(tmp_path: Path) -> None:
+    """AUTHORING.md documents the one-column rule and renders the live palette.
+
+    The width section states the Western-monospace assumption, and the safe
+    palette is generated from ``textwidth.SAFE_PALETTE`` (same can't-drift
+    pattern as the bands table) — every glyph appears, in a backticked cell.
+    """
+    from understone.engine.textwidth import SAFE_PALETTE
+
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+
+    assert "## Glyph width" in manual
+    assert "exactly one terminal column" in manual
+    assert "Western monospace" in manual  # the stated assumption
+    assert "Safe glyph palette" in manual
+    for glyph in SAFE_PALETTE:
+        assert f"`{glyph}`" in manual, f"palette glyph {glyph!r} missing from manual"
+
+
+def test_cli_newpack_authoring_md_documents_action_sets(tmp_path: Path) -> None:
+    """AUTHORING.md documents each building's real verb menu.
+
+    The per-building menus are an explicit table: the inn's `gamble` (v0.8) and
+    the v0.10 vault verbs `deposit`/`withdraw`, the shop's `forge`, and so on.
+    This pins the table rows and the "quaff anywhere" note so a doc regression
+    trips.
+    """
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+
+    assert "| `inn` | `rest`, `deposit`, `withdraw`, `gamble`, `leave` |" in manual
+    assert "| `shop` | `buy`, `sell`, `forge`, `leave` |" in manual
+    assert "| `healer` | `heal`, `leave` |" in manual
+    assert "| `dungeon` | `descend`, `challenge`, `leave` |" in manual
+    assert "`quaff`" in manual and "legal **anywhere**" in manual
+    # The vault is described where its verbs are listed.
+    assert "VAULT" in manual and "SAFE from ambush" in manual
+
+
+def test_cli_newpack_authoring_md_documents_ore_forge(tmp_path: Path) -> None:
+    """AUTHORING.md documents the v0.10 ore-gated forge: material slot + settings.
+
+    The forge ore is a `material` item earned in combat; the four ore settings
+    (item, per-plus, dungeon drop, forest chance) are documented, and the band
+    figures are generated from the live loader so they cannot drift.
+    """
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+
+    assert "`material`" in manual  # the new slot
+    assert "forge_ore_item" in manual
+    assert "ore_forest_chance" in manual  # the float setting (prose, not the band table)
+    # The two banded ore settings carry their LIVE bands.
+    lo, hi = loader.SETTINGS_BANDS["ore_dungeon_drop"]
+    assert f"`{lo}..{hi}`" in manual
+    assert "earns in combat" in manual or "earned in combat" in manual
+
+
+def test_cli_newpack_authoring_md_states_color_advisory_and_spawn_walkable(
+    tmp_path: Path,
+) -> None:
+    """AUTHORING.md states color is advisory (loader does not validate it) and
+    that spawn must be on walkable terrain — both v0.8 honesty fixes."""
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+
+    # color is documented as advisory / not validated (it matches loader behaviour).
+    assert "advisory and not validated" in manual
+    # spawn's walkability requirement is now stated where spawn is introduced.
+    assert "must be on walkable terrain" in manual
+
+
+def test_cli_newpack_authoring_md_color_roles_generated_from_enum(tmp_path: Path) -> None:
+    """AUTHORING.md's colour-role vocabulary is generated from the Color enum.
+
+    The v0.9 fix: the assignable roles were hand-listed (and went stale — road
+    and the per-building roles were missing). They are now generated from
+    ``Color.assignable()`` — the single source for the overlay-vs-assignable
+    split — so the manual lists exactly what the Watch can paint and cannot
+    drift. This asserts the NEW roles appear, that every assignable enum role
+    appears, and that the non-assignable roles (overlays + DEFAULT) are NOT
+    offered as author-assignable.
+    """
+    from understone.screen.palette import Color
+
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+
+    # A sampling of the new v0.9 roles is offered in the manual, backticked.
+    for role in ("road", "forest", "lava", "barren", "inn", "shop", "healer"):
+        assert f"`{role}`" in manual, f"new colour role {role!r} missing from manual"
+
+    # EVERY assignable enum role appears (generated, so the full set is present).
+    color_section = manual[manual.index("`color` — a palette role string") :].split("###", 1)[0]
+    for role in Color.assignable():
+        assert f"`{role.value}`" in manual, f"assignable role {role.value!r} missing from manual"
+
+    # The non-assignable roles (runtime overlays + the DEFAULT fallback) are NOT
+    # offered as terrain/location colours.
+    non_assignable = {c for c in Color} - set(Color.assignable())
+    assert Color.DEFAULT in non_assignable  # the fallback is not author-pickable
+    for role in non_assignable:
+        assert f"`{role.value}`" not in color_section, (
+            f"non-assignable role {role.value!r} wrongly offered as author-assignable"
+        )
+
+
+def test_cli_newpack_authoring_md_has_validate_coverage_split(tmp_path: Path) -> None:
+    """AUTHORING.md honestly separates machine-enforced rules from eyeball-only.
+
+    The v0.8 subsection lists what `validate` DOES catch (including the two new
+    enforcements — rare-as-guardian and single-boss) and what it does NOT (chief
+    among them: location menu `actions` contents are unvalidated).
+    """
+    dest = tmp_path / "mypack"
+    cli.cli_newpack(dest, out=StringIO(), err=StringIO())
+    manual = (dest / "AUTHORING.md").read_text(encoding="utf-8")
+
+    assert "What `validate` checks, and what it cannot" in manual
+    # The newly-enforced rules are named in the DOES-catch list.
+    assert "Exactly one boss" in manual
+    assert "fixed rung guardian) must" in manual  # rare-as-guardian enforcement
+    # The eyeball-only short list names the actions gap and the flavour caveat.
+    assert "Location menu `actions` contents" in manual
+    assert "Flavour and narration quality" in manual
+
+
+def test_cli_newpack_refuses_non_empty_dir(tmp_path: Path) -> None:
+    dest = tmp_path / "occupied"
+    dest.mkdir()
+    (dest / "keep.txt").write_text("mine", encoding="utf-8")
+
+    out, err = StringIO(), StringIO()
+    rc = cli.cli_newpack(dest, out=out, err=err)
+
+    assert rc == 2
+    assert "non-empty" in err.getvalue()
+    # The pre-existing file is untouched (nothing was scaffolded over it).
+    assert (dest / "keep.txt").read_text(encoding="utf-8") == "mine"
+    assert not (dest / "AUTHORING.md").exists()
+
+
+def test_cli_newpack_into_empty_existing_dir_succeeds(tmp_path: Path) -> None:
+    """An existing but empty directory is a fine scaffold target."""
+    dest = tmp_path / "empty"
+    dest.mkdir()
+    assert cli.cli_newpack(dest, out=StringIO(), err=StringIO()) == 0
+    assert (dest / "AUTHORING.md").exists()
+
+
+# ---------------------------------------------------------------------------
+# server.main argv dispatch
+# ---------------------------------------------------------------------------
+
+
+def test_main_validate_dispatch_returns_status(
+    tmp_path: Path, capsys: pytest.CaptureFixture
+) -> None:
+    # A broken pack routed through main exits 2; a sound one exits 0.
+    pack = _clone_shipped(tmp_path)
+    _patch_world(pack, _break_daily_turns)
+
+    with pytest.raises(SystemExit) as broken:
+        server.main(["validate", str(pack)])
+    assert broken.value.code == 2
+
+    with pytest.raises(SystemExit) as sound:
+        server.main(["validate", str(SHIPPED)])
+    assert sound.value.code == 0
+    assert "The door stands open." in capsys.readouterr().out
+
+
+def test_main_newpack_dispatch(tmp_path: Path) -> None:
+    dest = tmp_path / "viamain"
+    with pytest.raises(SystemExit) as exc:
+        server.main(["newpack", str(dest)])
+    assert exc.value.code == 0
+    assert (dest / "AUTHORING.md").exists()
+
+
+def test_main_worlds_dispatch(capsys: pytest.CaptureFixture) -> None:
+    """`understone worlds` routes through main, exits 0, and lists the Vale."""
+    with pytest.raises(SystemExit) as exc:
+        server.main(["worlds"])
+    assert exc.value.code == 0
+    out = capsys.readouterr().out
+    assert "vale" in out
+    assert "The Vale of Understone" in out
+    assert "UNDERSTONE_WORLD=" in out
+
+
+def test_bare_invocation_resolves_to_serve_without_side_effects() -> None:
+    """Parsing no argv yields the serve path, and parsing has no side effects.
+
+    The transport launch (_serve) is reachable, but argument parsing neither
+    loads a world nor binds a port — so this asserts the resolved command
+    without ever calling _serve.
+    """
+    args = server._build_parser().parse_args([])
+    assert args.cmd is None  # None => the serve branch in main()
+    assert callable(server._serve)
+
+
+def test_subprocess_validate_packaged_world_exits_zero() -> None:
+    """End-to-end smoke: `python -m understone validate <packaged dir>` exits 0."""
+    result = subprocess.run(
+        [sys.executable, "-m", "understone", "validate", str(SHIPPED)],
+        cwd=EXAMPLE_DIR,
+        capture_output=True,
+        text=True,
+        timeout=60,
+    )
+    assert result.returncode == 0, result.stderr
+    assert "The door stands open." in result.stdout
+
+
+# ---------------------------------------------------------------------------
+# helpers
+# ---------------------------------------------------------------------------
+
+
+def _clone_shipped(tmp_path: Path) -> Path:
+    dest = tmp_path / "pack"
+    shutil.copytree(SHIPPED, dest)
+    return dest
+
+
+def _patch_world(pack: Path, mutate: Callable[[dict[str, Any]], None]) -> None:
+    path = pack / "world.json"
+    data = json.loads(path.read_text(encoding="utf-8"))
+    mutate(data)
+    path.write_text(json.dumps(data), encoding="utf-8")
+
+
+def _break_daily_turns(data: dict[str, Any]) -> None:
+    """Set daily_turns out of its 1..100 band so the pack fails to load."""
+    data["settings"]["daily_turns"] = 0

examples/door-game/tests/test_combat.py

@@ -0,0 +1,123 @@
+"""Combat resolution tests.
+
+Pins determinism (a fixed seed yields identical results twice, log and
+deltas), each outcome (win/lose/flee), xp/gold crediting on victory, and
+the defeat contract: the result flags a spawn bounce with no xp/gold and a
+zero hp delta (the façade applies hp=1 and the move).
+"""
+
+from __future__ import annotations
+
+from tests.conftest import make_monster, make_player
+from understone.engine.combat import Outcome, resolve_fight, resolve_flee
+from understone.engine.rng import GameRNG
+
+# A strong adventurer vs a Field Rat wins on every probed seed.
+_WIN_SEED = 1
+# A fragile adventurer vs a Stone Wyrm loses on every probed seed.
+_LOSE_SEED = 0
+# Flee outcomes (probed): seed 1 escapes clean, seed 0 is caught.
+_FLEE_CLEAN_SEED = 1
+_FLEE_CAUGHT_SEED = 0
+
+
+def _strong_player() -> object:
+    return make_player(hp=20, max_hp=20, atk=5, def_=1, xp=0, gold=50)
+
+
+def _wyrm() -> object:
+    return make_monster(tier=5, name="Stone Wyrm", hp=60, atk=18, def_=6, xp=140, gold=60)
+
+
+def test_fight_is_deterministic_under_fixed_seed() -> None:
+    r1 = resolve_fight(GameRNG(seed=7), make_player(), make_monster())
+    r2 = resolve_fight(GameRNG(seed=7), make_player(), make_monster())
+    assert r1.log == r2.log
+    assert (r1.outcome, r1.xp_delta, r1.gold_delta, r1.hp_delta) == (
+        r2.outcome,
+        r2.xp_delta,
+        r2.gold_delta,
+        r2.hp_delta,
+    )
+
+
+def test_win_credits_xp_and_gold() -> None:
+    player = make_player(hp=20, max_hp=20, atk=5, def_=1)
+    monster = make_monster(hp=6, atk=3, def_=0, xp=8, gold=3)
+    result = resolve_fight(GameRNG(seed=_WIN_SEED), player, monster)
+    assert result.outcome is Outcome.WIN
+    assert result.xp_delta == 8
+    assert result.gold_delta == 3
+    # hp_delta is non-positive (you may take a scratch) and never fatal here.
+    assert result.hp_delta <= 0
+    assert not result.bounce_to_spawn
+
+
+def test_win_deltas_are_exact_for_pinned_seed() -> None:
+    player = make_player(hp=20, max_hp=20, atk=5, def_=1)
+    monster = make_monster(hp=6, atk=3, def_=0, xp=8, gold=3)
+    result = resolve_fight(GameRNG(seed=_WIN_SEED), player, monster)
+    # Pinned from a determinism probe; guards against silent damage drift.
+    assert result.hp_delta == -1
+    # The engine no longer emits a "falls + reward" line — that sentence is
+    # composed by the game façade where the xp/gold are actually banked — so
+    # the WIN log is one line shorter than before and ends on the kill blow.
+    assert len(result.log) == 4
+    assert result.log[-1] == "You strike for 6. (Field Rat: 0 HP)"
+
+
+def test_win_log_does_not_claim_rewards() -> None:
+    """The engine narrates the kill blow only; it never claims xp/gold itself.
+
+    Reward ownership lives in the façade (so the Wyrm-win legacy reset, which
+    keeps no xp/gold, narrates no reward). The deltas are still carried on the
+    result for the caller to apply.
+    """
+    player = make_player(hp=20, max_hp=20, atk=5, def_=1)
+    monster = make_monster(hp=6, atk=3, def_=0, xp=8, gold=3)
+    result = resolve_fight(GameRNG(seed=_WIN_SEED), player, monster)
+    assert result.outcome is Outcome.WIN
+    assert result.xp_delta == 8 and result.gold_delta == 3  # deltas still set
+    joined = "\n".join(result.log)
+    assert "falls" not in joined  # no kill/reward sentence in the engine log
+    assert "XP" not in joined and "gold" not in joined
+
+
+def test_loss_flags_bounce_without_rewards() -> None:
+    result = resolve_fight(GameRNG(seed=_LOSE_SEED), _strong_player_loses(), _wyrm())
+    assert result.outcome is Outcome.LOSE
+    assert result.bounce_to_spawn is True
+    assert result.xp_delta == 0
+    assert result.gold_delta == 0
+    # Combat does not set hp to 1 itself — that is the façade's job.
+    assert result.hp_delta == 0
+
+
+def _strong_player_loses() -> object:
+    return make_player(hp=12, max_hp=12, atk=4, def_=0)
+
+
+def test_flee_can_escape_clean() -> None:
+    player = make_player(hp=20, max_hp=20, def_=1)
+    monster = make_monster(atk=8, def_=2)
+    result = resolve_flee(GameRNG(seed=_FLEE_CLEAN_SEED), player, monster)
+    assert result.outcome is Outcome.FLED
+    assert result.hp_delta == 0
+
+
+def test_flee_caught_costs_hp_but_never_kills() -> None:
+    player = make_player(hp=20, max_hp=20, def_=1)
+    monster = make_monster(atk=8, def_=2)
+    result = resolve_flee(GameRNG(seed=_FLEE_CAUGHT_SEED), player, monster)
+    assert result.outcome is Outcome.FLED
+    assert result.hp_delta < 0
+    # A caught flight cannot drop the player to or below zero.
+    assert player.hp + result.hp_delta >= 1
+
+
+def test_flee_caught_never_kills_at_low_hp() -> None:
+    player = make_player(hp=1, max_hp=20, def_=0)
+    monster = make_monster(atk=40, def_=0)
+    result = resolve_flee(GameRNG(seed=_FLEE_CAUGHT_SEED), player, monster)
+    # At 1 HP the most a failed flee can cost is 0 (cannot go below 1).
+    assert result.hp_delta == 0

examples/door-game/tests/test_game.py

@@ -0,0 +1,858 @@
+"""Game façade integration tests over the shipped world.
+
+Drives a full session against a temp store, a frozen clock, and a seeded
+RNG: join -> status -> look -> move -> action(buy/rest/fight) -> log ->
+rank -> bestow. Persistence is exercised by reopening the store.
+
+Negative-test discipline (turn guard and bestow cap):
+  Two guards are pinned by assertions here. To confirm each assertion has
+  teeth, the implementer temporarily reverted the guard line and observed
+  the matching test FAIL, then restored it:
+
+  * Turn guard (engine/turns.py spend_turn): replacing
+    ``if player.turns_left <= 0: return False`` with ``return True``
+    let fighting continue past the daily budget — ``test_turn_budget_blocks``
+    then failed on the "spent for today" assertion. Restored.
+  * Bestow cap (game.py bestow): removing the ``if cost > remaining``
+    refusal let an over-budget bestowal through — ``test_bestow_cap_refuses``
+    then failed on the unchanged-gold assertion. Restored.
+  * Sanitizer control-char guard (game.py _sanitize): disabling the
+    ``not cleaned.isprintable()`` clause let a newline-injected name create a
+    player row and a public event — ``test_join_rejects_control_char_name``
+    then failed. Restored. (See the comment block above the hygiene tests.)
+"""
+
+from __future__ import annotations
+
+import unicodedata
+from pathlib import Path
+
+import pytest
+
+from tests.conftest import fixed_clock, utc
+from understone.engine.models import Mode
+from understone.engine.rng import GameRNG
+from understone.game import Game
+from understone.persistence import Store
+from understone.world.loader import load_world
+
+PACK = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+
+@pytest.fixture
+def clock() -> object:
+    return fixed_clock(utc(2026, 6, 12, 10, 0))
+
+
+def _game(tmp_path: Path, clock: object, seed: int = 7) -> Game:
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    return Game(world, store, clock=clock, rng=GameRNG(seed=seed))  # type: ignore[arg-type]
+
+
+# ---------------------------------------------------------------------------
+# Join / status / look
+# ---------------------------------------------------------------------------
+
+
+def test_join_creates_player_at_spawn(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    out = game.join("Brandr")
+    player = game.players["Brandr"]
+    assert (player.x, player.y) == game.world.spawn
+    assert player.gold == game.world.settings.starting_gold
+    assert "@" in out
+    assert game.world.name in out
+
+
+def test_join_resumes_existing(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.players["Brandr"].gold = 123
+    out = game.join("Brandr")
+    assert "Welcome back" in out
+    assert game.players["Brandr"].gold == 123
+
+
+def test_status_unknown_player_is_friendly(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    out = game.status("Nobody")
+    assert "has signed the ledger" in out
+    assert "door_join" in out
+
+
+def test_look_overworld_has_frame(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    out = game.look("Brandr")
+    assert "@" in out
+    assert "┌" in out and "┐" in out
+    assert len(out) < 2048
+
+
+def test_overworld_frame_textured_borders_intact(tmp_path: Path, clock: object) -> None:
+    """The textured overworld frame keeps square borders and a single player marker.
+
+    Structural discipline for the v0.6 texture: variants change the GLYPHS but
+    must never change the geometry. The box rows are uniform width, exactly one
+    '@' is painted, and the grass field shows more than one variant in a row
+    (the deterministic stipple, not a flat sheet of '.').
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    frame = game.look("Brandr")
+    lines = frame.split("\n")
+    # Box rows: top border + VIEW_H grid rows + bottom border, all equal width.
+    box = [ln for ln in lines if ln and ln[0] in "┌│└"]
+    widths = {len(ln) for ln in box}
+    assert len(widths) == 1, f"textured frame rows ragged: {widths}"
+    # Exactly one player marker, regardless of the surrounding texture.
+    assert frame.count("@") == 1
+    # The grass texture varies: a body row carries at least two of . , '
+    body = [ln for ln in lines if ln.startswith("│")]
+    assert any(len({ch for ch in ln if ch in ".,'"}) >= 2 for ln in body)
+
+
+def test_look_in_menu_shows_location(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    # Shop is two cells east of spawn along the road.
+    game.move("Brandr", "", "east", 2)
+    assert game.players["Brandr"].mode is Mode.MENU
+    out = game.look("Brandr")
+    assert "(B)uy" in out and "(L)eave" in out
+
+
+# ---------------------------------------------------------------------------
+# Move
+# ---------------------------------------------------------------------------
+
+
+def test_move_blocked_in_menu(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.move("Brandr", "", "east", 2)  # into the shop menu
+    out = game.move("Brandr", "", "east", 2)
+    assert "inside" in out.lower()
+
+
+def test_move_enters_location(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    out = game.move("Brandr", "", "west", 2)  # inn is two cells west
+    assert game.players["Brandr"].at_location == "inn"
+    assert "step inside" in out.lower()
+
+
+# ---------------------------------------------------------------------------
+# Actions: rest, fight, turn budget
+# ---------------------------------------------------------------------------
+
+
+def test_rest_heals_and_charges(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    player.hp = 5
+    game.move("Brandr", "", "west", 2)  # inn
+    out = game.action("Brandr", "rest", "", "")
+    assert player.hp == player.max_hp
+    assert player.gold == game.world.settings.starting_gold - game.world.settings.rest_cost
+    assert "full health" in out.lower()
+
+
+def test_rest_when_spent_restores_a_fresh_days_turns(tmp_path: Path, clock: object) -> None:
+    """Sleeping at the inn with no turns left rolls into a fresh day's allowance."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    daily = game.world.settings.daily_turns
+    player.turns_left = 0  # spent for the day
+    player.hp = 5
+    game.move("Brandr", "", "west", 2)  # step into the inn
+    out = game.action("Brandr", "rest", "", "")
+    assert player.turns_left == daily  # a fresh day's turns restored
+    assert player.hp == player.max_hp  # and fully mended
+    assert f"/{daily} ]" in out  # footer reflects the refreshed budget
+
+
+def test_rest_with_turns_in_hand_never_inflates_the_budget(tmp_path: Path, clock: object) -> None:
+    """Resting mid-day mends but adds no turns — the top-up only fires at zero."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    daily = game.world.settings.daily_turns
+    player.turns_left = daily - 3  # turns still in hand
+    player.hp = 5
+    game.move("Brandr", "", "west", 2)  # step into the inn
+    game.action("Brandr", "rest", "", "")
+    assert player.turns_left == daily - 3  # unchanged: no farming past the cap
+    assert player.hp == player.max_hp  # but the heal still lands
+
+
+def test_fight_spends_a_turn_and_credits(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    # Drop into the forest_near zone so an encounter is available.
+    player.x, player.y = 35, 25
+    before_turns = player.turns_left
+    out = game.action("Brandr", "fight", "", "")
+    assert player.turns_left == before_turns - 1
+    assert player.xp > 0
+    assert "XP" in out
+
+
+def test_turn_budget_blocks(tmp_path: Path, clock: object) -> None:
+    """Pins the spend_turn guard: at 0 turns, fighting is refused.
+
+    See the module docstring for the revert-and-observe-failure check that
+    proves this assertion has teeth.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    player.x, player.y = 35, 25
+    player.turns_left = 0
+    out = game.action("Brandr", "fight", "", "")
+    assert "spent for today" in out.lower()
+    # No turn was consumed past zero, and no XP was gained.
+    assert player.turns_left == 0
+    assert player.xp == 0
+
+
+# ---------------------------------------------------------------------------
+# Log / rank
+# ---------------------------------------------------------------------------
+
+
+def test_log_reports_then_advances(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    # A second player acting creates a public event Brandr has not yet seen.
+    game.join("Sigrun")
+    first = game.log("Brandr")
+    assert "Sigrun" in first or "Brandr" in first
+    assert "The Understone Herald" in first  # dressed as the broadsheet
+    # The cursor advanced; a second read with no new events is quiet.
+    second = game.log("Brandr")
+    assert "The Understone Herald" in second  # the masthead still prints
+    assert "still" in second.lower()  # the herald-flavoured "all quiet" line
+
+
+def test_rank_marks_caller(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.join("Sigrun")
+    game.players["Sigrun"].level = 5
+    out = game.rank("Brandr")
+    assert "Brandr" in out and "Sigrun" in out
+    assert "*" in out  # the caller's row is marked
+    assert "┌" in out  # box-drawing table
+
+
+# ---------------------------------------------------------------------------
+# Rank ★ column: stars live in their own column, so a long name keeps them
+# ---------------------------------------------------------------------------
+
+
+def test_win_stars_column_formats() -> None:
+    """Zero is blank, 1..5 render as ★ runs, and >5 collapses to ★xN."""
+    from understone.game import _win_stars
+
+    assert _win_stars(0) == ""
+    assert _win_stars(1) == "★"
+    assert _win_stars(5) == "★★★★★"
+    assert _win_stars(7) == "★x7"
+
+
+def test_long_name_with_one_win_keeps_its_star() -> None:
+    """A full 24-char name no longer eats its own ★ (the v0.1 truncation bug).
+
+    The name occupied the whole 20-wide field before, clipping the star away;
+    with a separate stars column the ★ survives beside a maximal name.
+    """
+    from understone.engine.rank import RankEntry
+    from understone.game import _render_rank_table
+
+    name = "X" * 24
+    rows = _render_rank_table([RankEntry(name=name, level=5, xp=100, gold=50, wins=1)], caller="")
+    body = "\n".join(rows)
+    assert name in body  # the full name is present
+    assert "★" in body  # and so is its star
+
+
+def test_high_win_count_renders_compact_marker() -> None:
+    """Seven wins render as the compact ``★x7`` rather than seven glyphs."""
+    from understone.engine.rank import RankEntry
+    from understone.game import _render_rank_table
+
+    rows = _render_rank_table([RankEntry(name="Champ", level=9, xp=9, gold=9, wins=7)], caller="")
+    body = "\n".join(rows)
+    assert "★x7" in body
+    assert "★★★★★★★" not in body  # not seven literal stars
+
+
+def test_shared_world_other_player_marker(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.join("Sigrun")
+    # Stand Sigrun one cell east of Brandr's spawn so she lands in the view.
+    sig = game.players["Sigrun"]
+    brandr = game.players["Brandr"]
+    sig.x, sig.y = brandr.x + 1, brandr.y
+    out = game.look("Brandr")
+    assert "☻" in out  # the other player shows as '☻'
+
+
+# ---------------------------------------------------------------------------
+# Bestow (+ cap negative test)
+# ---------------------------------------------------------------------------
+
+
+def test_bestow_grants_gold(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    before = player.gold
+    out = game.bestow("Brandr", "a daring rescue", 10, 0)
+    assert player.gold == before + 10
+    assert player.bestow_spent == 10
+    assert "bestowal" in out.lower()
+
+
+def test_bestow_heal_charges_only_applied(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    player.hp = player.max_hp - 3  # only 3 missing
+    game.bestow("Brandr", "mercy after a hard fight", 0, 10)
+    assert player.hp == player.max_hp
+    # Charged for 3 HP at heal_cost_per_hp, not the requested 10.
+    assert player.bestow_spent == 3 * game.world.settings.heal_cost_per_hp
+
+
+def test_bestow_requires_reason(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    out = game.bestow("Brandr", "   ", 10, 0)
+    assert "reason" in out.lower()
+    assert game.players["Brandr"].gold == game.world.settings.starting_gold
+
+
+def test_bestow_requires_nonzero(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    out = game.bestow("Brandr", "nothing at all", 0, 0)
+    assert "at least" in out.lower()
+
+
+def test_bestow_cap_refuses(tmp_path: Path, clock: object) -> None:
+    """Pins the bestow cap: an over-budget grant is refused without mutation.
+
+    See the module docstring for the revert-and-observe-failure check that
+    proves this assertion has teeth.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    budget = game.world.settings.bestow_daily_budget
+    before_gold = player.gold
+    out = game.bestow("Brandr", "an absurd windfall", budget + 100, 0)
+    assert "the fates allow" in out.lower()
+    # Refused cleanly: no gold moved and no pool spent.
+    assert player.gold == before_gold
+    assert player.bestow_spent == 0
+
+
+def test_bestow_pool_resets_next_day(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    game.bestow("Brandr", "first blessing", 20, 0)
+    assert player.bestow_spent == 20
+    # Advance the clock past UTC midnight; the next bestow sees a fresh pool.
+    game.clock = fixed_clock(utc(2026, 6, 13, 0, 5))  # type: ignore[assignment]
+    game.bestow("Brandr", "a new day's fortune", 20, 0)
+    assert player.bestow_spent == 20  # reset to 0 then +20, not 40
+
+
+# ---------------------------------------------------------------------------
+# Persistence round-trip through the façade
+# ---------------------------------------------------------------------------
+
+
+def test_state_survives_store_reopen(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.players["Brandr"].x, game.players["Brandr"].y = 35, 25
+    game.action("Brandr", "fight", "", "")
+    xp_after = game.players["Brandr"].xp
+    gold_after = game.players["Brandr"].gold
+    game.store.close()
+
+    world = load_world(PACK)
+    reopened = Store(tmp_path / "game.db")
+    revived = Game(world, reopened, clock=clock)  # type: ignore[arg-type]
+    assert revived.players["Brandr"].xp == xp_after
+    assert revived.players["Brandr"].gold == gold_after
+
+
+# ---------------------------------------------------------------------------
+# Day rollover applies to fight/descend, not just join/bestow
+# ---------------------------------------------------------------------------
+
+
+class _MutableClock:
+    """A clock whose reported moment can be advanced between calls."""
+
+    def __init__(self, moment: object) -> None:
+        self.moment = moment
+
+    def __call__(self) -> object:
+        return self.moment
+
+
+def test_fight_refreshes_budget_across_midnight(tmp_path: Path) -> None:
+    """A fight on a new UTC day must reset the budget without re-joining.
+
+    Before the fix, _resolve_encounter spent a turn without calling
+    _ensure_day, so an exhausted player who returned the next day was still
+    blocked until they happened to re-join.
+    """
+    clk = _MutableClock(utc(2026, 6, 12, 23, 0))
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    game = Game(world, store, clock=clk, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    player.x, player.y = 35, 25  # forest_near zone: an encounter is available
+    player.turns_left = 0  # spent for the day
+    daily = game.world.settings.daily_turns
+
+    clk.moment = utc(2026, 6, 13, 0, 5)  # cross UTC midnight, no re-join
+    out = game.action("Brandr", "fight", "", "")
+
+    assert "spent for today" not in out.lower()  # the fresh day let the fight run
+    assert player.turns_left == daily - 1  # reset to full, then one spent
+    assert player.xp > 0
+    assert f"/{daily} ]" in out  # footer shows the refreshed budget
+
+
+def test_descend_refreshes_budget_across_midnight(tmp_path: Path) -> None:
+    """Descending on a new UTC day resets the budget without re-joining."""
+    clk = _MutableClock(utc(2026, 6, 12, 23, 0))
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    game = Game(world, store, clock=clk, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    game.join("Hero")
+    player = game.players["Hero"]
+    # Overwhelming stats so the gauntlet itself never bounces the player.
+    player.level, player.atk, player.def_ = 20, 200, 100
+    player.hp = player.max_hp = 500
+    player.mode = Mode.MENU
+    player.at_location = "dungeon"
+    player.turns_left = 0
+    daily = game.world.settings.daily_turns
+
+    clk.moment = utc(2026, 6, 13, 0, 5)
+    out = game.action("Hero", "descend", "", "")
+
+    assert "too weary" not in out.lower()
+    assert player.turns_left == daily - 1
+
+
+# ---------------------------------------------------------------------------
+# Input hygiene chokepoint (the _sanitize helper)
+# ---------------------------------------------------------------------------
+#
+# Negative-test discipline (security invariant): to prove the control-char
+# rejection in Game._sanitize has teeth, the implementer temporarily replaced
+# its ``not cleaned.isprintable()`` clause with ``False`` (disabling the
+# check) and confirmed test_join_rejects_control_char_name FAILED — the
+# injected name created a player row and a public event. The clause was then
+# restored. The newline-injection test below is the standing regression for
+# that invariant.
+
+
+def test_join_rejects_control_char_name(tmp_path: Path, clock: object) -> None:
+    """A bell/control character in a name is refused with the runes line."""
+    game = _game(tmp_path, clock)
+    out = game.join("Bra\x07ndr")
+    assert "strange runes" in out
+    assert game.players == {}  # no row created
+    assert game.events == []  # nothing persisted
+
+
+def test_join_rejects_newline_name_no_persist(tmp_path: Path, clock: object) -> None:
+    """An embedded newline (log-injection vector) is refused, nothing written.
+
+    The name is kept short so it is the control-char clause — not the length
+    clause — that rejects it; this is the standing regression for the
+    isprintable security invariant documented in the module docstring.
+    """
+    game = _game(tmp_path, clock)
+    out = game.join("Bra\nndr")  # 7 chars: well under the 24 limit
+    assert "strange runes" in out  # the runes (bad-character) refusal, not length
+    # The security invariant: no player row and no event row escaped the guard.
+    assert game.players == {}
+    assert game.events == []
+
+
+def test_join_rejects_overlong_name(tmp_path: Path, clock: object) -> None:
+    """A 25-character name is refused with the narrow-ledger line."""
+    game = _game(tmp_path, clock)
+    out = game.join("X" * 25)
+    assert "ledger is narrow" in out
+    assert game.players == {}
+
+
+def test_join_accepts_max_length_name(tmp_path: Path, clock: object) -> None:
+    """A 24-character name is exactly at the limit and accepted."""
+    game = _game(tmp_path, clock)
+    name = "X" * 24
+    game.join(name)
+    assert name in game.players
+
+
+# ---------------------------------------------------------------------------
+# Narrow-ledger width rule (the _sanitize one-column clause, v0.6)
+#
+# Names/reasons/mail render inside fixed-width frames and tables, so a glyph
+# that does not fit a single column would shove a column out of true. The
+# sanitizer rejects wide runes and combining marks; a printable-but-wide name
+# gets the dedicated narrow-ledger refusal, not the control-char "runes" line.
+# ---------------------------------------------------------------------------
+
+
+def test_join_rejects_wide_cjk_name(tmp_path: Path, clock: object) -> None:
+    """A CJK ideograph name is refused with the narrow-ledger line; nothing written."""
+    game = _game(tmp_path, clock)
+    out = game.join("龍")
+    assert "columns are narrow" in out
+    assert game.players == {}
+    assert game.events == []
+
+
+def test_join_rejects_emoji_name(tmp_path: Path, clock: object) -> None:
+    """An emoji in a name (🌲x) is wide and refused with the narrow-ledger line."""
+    game = _game(tmp_path, clock)
+    out = game.join("🌲x")
+    assert "columns are narrow" in out
+    assert game.players == {}
+
+
+def test_join_rejects_fullwidth_name(tmp_path: Path, clock: object) -> None:
+    """A fullwidth Latin letter (Ａ) is two columns and refused."""
+    game = _game(tmp_path, clock)
+    out = game.join("Ａ")
+    assert "columns are narrow" in out
+    assert game.players == {}
+
+
+def test_join_rejects_combining_mark_name(tmp_path: Path, clock: object) -> None:
+    """A name with a combining mark (decomposed accent) is refused as wide.
+
+    The name is normalised to NFD so the 'o' carries a separate U+0308
+    combining diaeresis — a zero-width code point that desynchronises the
+    column count. Built explicitly so the source encoding cannot mask it.
+    """
+    game = _game(tmp_path, clock)
+    decomposed = unicodedata.normalize("NFD", "Bj\u00f6rn")
+    assert any(unicodedata.combining(ch) for ch in decomposed)  # genuinely NFD
+    out = game.join(decomposed)
+    assert "columns are narrow" in out
+    assert game.players == {}
+
+
+def test_join_accepts_composed_latin_name(tmp_path: Path, clock: object) -> None:
+    """A precomposed Latin accent (NFC name) is all single-column and accepted."""
+    game = _game(tmp_path, clock)
+    composed = unicodedata.normalize("NFC", "Bj\u00f6rn")
+    game.join(composed)
+    assert composed in game.players
+
+
+def _seed_wide_named_player(db: Path, clock: object, wide_name: str) -> None:
+    """Write a stored adventurer whose name is a now-illegal wide rune.
+
+    Bypasses ``join`` (which would refuse a wide name at creation) by upserting
+    a Player row straight through the Store, so the fixture stands in for a save
+    that predates the narrow-ledger rule. Built by renaming a legitimately-
+    created hero so every other field stays valid.
+    """
+    from dataclasses import replace
+
+    world = load_world(PACK)
+    seed = Store(db)
+    game = Game(world, seed, clock=clock, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    game.join("Brandr")
+    base = game.players["Brandr"]
+    seed.upsert_player(replace(base, name=wide_name))
+    seed.commit()
+    seed.close()
+
+
+def test_join_resumes_stored_wide_name(tmp_path: Path, clock: object) -> None:
+    """An existing adventurer with a wide-rune name resumes \u2014 identity is never re-gated.
+
+    Resume keys off the exact stored name BEFORE the sanitizer, so a character
+    whose name predates the narrow-ledger rule is welcomed back rather than
+    locked out. This is the resume-by-exact-name invariant.
+    """
+    db = tmp_path / "game.db"
+    wide = "\u9f8d"
+    _seed_wide_named_player(db, clock, wide)
+
+    world = load_world(PACK)
+    game = Game(world, Store(db), clock=clock, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    out = game.join(wide)
+    assert "Welcome back" in out  # resumed, not refused
+    assert "columns are narrow" not in out
+    assert wide in game.players
+
+
+def test_join_still_refuses_new_wide_name(tmp_path: Path, clock: object) -> None:
+    """Creation is still gated: a NEW wide name with no stored row is refused.
+
+    The resume bypass is exact-name only; a wide name that matches no stored
+    adventurer falls through to the creation gate and gets the narrow-ledger
+    refusal, with nothing written.
+    """
+    db = tmp_path / "game.db"
+    # Seed one wide-named save, then try to CREATE a different wide name.
+    _seed_wide_named_player(db, clock, "\u9f8d")
+
+    world = load_world(PACK)
+    game = Game(world, Store(db), clock=clock, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    out = game.join("\u7363")  # a different wide rune \u2014 no stored row for it
+    assert "columns are narrow" in out
+    assert "\u7363" not in game.players
+
+
+def test_bestow_rejects_newline_reason_no_persist(tmp_path: Path, clock: object) -> None:
+    """A newline-embedded bestow reason is refused; no event, pool unchanged."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    events_before = len(game.events)
+    out = game.bestow("Brandr", "heroics\nand a forged log line", 10, 0)
+    assert "plainly-spoken" in out
+    assert len(game.events) == events_before  # no bestow event appended
+    assert player.bestow_spent == 0  # pool untouched
+
+
+# ---------------------------------------------------------------------------
+# Bestow: heal-only at full HP grants nothing (no empty grant persisted)
+# ---------------------------------------------------------------------------
+
+
+def test_bestow_heal_only_at_full_hp_refused(tmp_path: Path, clock: object) -> None:
+    """A heal-only bestow at full HP applies nothing and must not persist."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    assert player.hp == player.max_hp  # join starts at full health
+    events_before = len(game.events)
+    out = game.bestow("Brandr", "a quiet blessing", 0, 10)
+    assert "already hale" in out
+    assert len(game.events) == events_before  # no "Fortune favours" line written
+    assert player.bestow_spent == 0  # nothing charged
+
+
+# ---------------------------------------------------------------------------
+# Descend the deep: one rung per descent (see test_descend.py for the ladder)
+# ---------------------------------------------------------------------------
+
+
+def test_descend_fights_one_rung_and_advances(tmp_path: Path, clock: object) -> None:
+    """A strong player clears the next rung: one foe fought, rewards banked, depth +1."""
+    game = _game(tmp_path, clock)
+    game.join("Hero")
+    player = game.players["Hero"]
+    player.level, player.atk, player.def_ = 20, 200, 100
+    player.hp = player.max_hp = 500
+    player.mode = Mode.MENU
+    player.at_location = "dungeon"
+    before_turns, before_gold, before_xp = player.turns_left, player.gold, player.xp
+
+    out = game.action("Hero", "descend", "", "")
+
+    # The first rung is the tier-3 guardian (Forest Wolf); deeper rungs do NOT
+    # appear in one descent — the deep is fought a rung at a time now.
+    assert "Forest Wolf" in out
+    assert "Cave Troll" not in out
+    assert player.deepest_rung == 1
+    assert player.turns_left == before_turns - 1
+    assert player.gold > before_gold
+    assert player.xp > before_xp
+
+
+def test_descend_bounces_weak_player_to_spawn(tmp_path: Path, clock: object) -> None:
+    """A fresh weak player falls on the first rung and wakes at the spawn.
+
+    Depth is NOT advanced by a loss, but it persists at whatever it was (here 0).
+    """
+    game = _game(tmp_path, clock)
+    game.join("Weakling")
+    player = game.players["Weakling"]
+    player.mode = Mode.MENU
+    player.at_location = "dungeon"
+
+    out = game.action("Weakling", "descend", "", "")
+
+    assert player.hp == 1
+    assert player.mode is Mode.TILE
+    assert player.at_location == ""
+    assert (player.x, player.y) == game.world.spawn
+    assert player.deepest_rung == 0  # a loss never advances the deep
+    # Felled by the first rung (the tier-3 Forest Wolf).
+    assert "Forest Wolf" in out
+
+
+# ---------------------------------------------------------------------------
+# Shop façade: buy / upgrade / sell / heal stat arithmetic
+# ---------------------------------------------------------------------------
+
+
+def test_shop_buy_upgrade_sell_heal_cycle(tmp_path: Path, clock: object) -> None:
+    """Equip deltas apply once on buy/upgrade and unwind cleanly on sell."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    player.gold = 1000
+    player.mode = Mode.MENU
+    player.at_location = "shop"
+
+    short_sword = game.world.item_by_id("short_sword")
+    war_axe = game.world.item_by_id("war_axe")
+    starter = game.world.item_by_id(game.world.settings.starting_weapon)
+    assert short_sword is not None and war_axe is not None and starter is not None
+
+    starter_atk = player.atk  # 3 base + rusty dagger bonus
+
+    # Buy the short sword: gold falls by its price, atk rises by the delta.
+    gold0 = player.gold
+    game.action("Brandr", "buy", "", "short_sword")
+    assert player.gold == gold0 - short_sword.price
+    assert player.atk == starter_atk + (short_sword.atk - starter.atk)
+    atk_with_sword = player.atk
+
+    # Upgrade to the war axe: atk reflects the difference, not a double-add.
+    gold1 = player.gold
+    game.action("Brandr", "buy", "", "war_axe")
+    assert player.gold == gold1 - war_axe.price
+    assert player.atk == atk_with_sword + (war_axe.atk - short_sword.atk)
+
+    # Sell the war axe: half-price refund, atk falls back to the starter bonus.
+    gold2 = player.gold
+    game.action("Brandr", "sell", "", "")
+    assert player.gold == gold2 + war_axe.price // 2
+    assert player.atk == starter_atk
+
+    # Heal at the shrine: HP restored, gold debited per missing point.
+    player.mode = Mode.MENU
+    player.at_location = "healer"
+    player.hp = player.max_hp - 5
+    per_hp = game.world.settings.heal_cost_per_hp
+    gold3 = player.gold
+    game.action("Brandr", "heal", "", "")
+    assert player.hp == player.max_hp
+    assert player.gold == gold3 - 5 * per_hp
+
+
+def test_sell_starter_weapon_refused(tmp_path: Path, clock: object) -> None:
+    """The starter blade is unsellable regardless of price (no free-gold loop)."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    assert player.weapon_id == game.world.settings.starting_weapon
+    player.mode = Mode.MENU
+    player.at_location = "shop"
+    gold_before = player.gold
+    out = game.action("Brandr", "sell", "", "")
+    assert "nothing worth selling" in out.lower()
+    assert player.gold == gold_before
+
+
+# ---------------------------------------------------------------------------
+# Bounded in-memory event tail (full history stays in SQLite)
+# ---------------------------------------------------------------------------
+
+
+def test_event_tail_is_capped_but_log_still_works(tmp_path: Path, clock: object) -> None:
+    """Loading caps the resident tail; door_log still serves recent events."""
+    from understone.engine.log import since
+    from understone.game import EVENT_TAIL_KEEP
+
+    db = tmp_path / "game.db"
+    seed_store = Store(db)
+    last_id = 0
+    for i in range(EVENT_TAIL_KEEP + 50):
+        last_id = seed_store.insert_event("t", "sys", "note", f"event {i}")
+    seed_store.commit()
+    seed_store.close()
+
+    world = load_world(PACK)
+    game = Game(world, Store(db), clock=clock, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    # Only the most recent EVENT_TAIL_KEEP events are resident in memory.
+    assert len(game.events) == EVENT_TAIL_KEEP
+    assert game.events[-1].event_id == last_id
+
+    # door_log still reports events after a recent cursor.
+    recent_cursor = game.events[-3].event_id
+    game.join("Brandr")
+    game.players["Brandr"].log_cursor = recent_cursor
+    out = game.log("Brandr")
+    assert "The Understone Herald" in out  # broadsheet masthead
+    assert "since your last visit" in out
+    fresh, new_cursor = since(game.events, recent_cursor)
+    assert fresh  # there are events past the cursor
+    assert new_cursor == game.events[-1].event_id
+
+
+def test_private_mail_survives_tail_eviction(tmp_path: Path, clock: object) -> None:
+    """A private note older than the resident tail is still delivered (durable mail).
+
+    Public history that falls off the in-memory tail is gone by design (the
+    broadsheet does not keep), but mail must not be: a note left while the
+    recipient was away has to surface however many public events have since
+    pushed it out of the tail. A third player — whose cursor also predates the
+    note — must still never see it, because it was never theirs.
+    """
+    from understone.persistence import EVENT_TAIL_KEEP
+
+    db = tmp_path / "game.db"
+    store = Store(db)
+    game = Game(load_world(PACK), store, clock=clock, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    game.join("Scribe")
+    game.join("Reader")
+    game.join("Bystander")
+    # Scribe leaves Reader a private note; neither Reader nor Bystander reads it.
+    secret = "the cellar key is under the third barrel"
+    game.action("Scribe", "post", "Reader", "", secret)
+
+    # Flood the feed past the tail bound so the note is evicted from memory.
+    for i in range(EVENT_TAIL_KEEP + 20):
+        store.insert_event("t", "sys", "note", f"broadsheet filler {i}")
+    store.commit()
+    store.close()
+
+    # Reopen: only the newest tail is resident, so the note now lives in the gap.
+    reopened = Store(db)
+    revived = Game(load_world(PACK), reopened, clock=clock, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    note_id = next(
+        e.event_id
+        for e in reopened.targeted_events_since("Reader", 0)  # note: from SQLite, not the tail
+        if secret in e.text
+    )
+    assert note_id < revived.events[0].event_id  # the note really is past the tail
+
+    # The recipient still sees the note, backfilled from SQLite...
+    reader_log = revived.log("Reader")
+    assert secret in reader_log
+    assert "While you were away" in reader_log
+    # ...but a third player never does, even though their cursor predates it too.
+    third_log = revived.log("Bystander")
+    assert secret not in third_log
+    reopened.close()

examples/door-game/tests/test_leveling.py

@@ -0,0 +1,118 @@
+"""XP curve, level-up, and restorative-maths tests.
+
+Pins the threshold edges (at / just below / just above), a multi-level
+jump from a single award, the exact growth table, the inn's flat-rate
+full heal with affordability gating, and the healer's per-HP cost maths.
+"""
+
+from __future__ import annotations
+
+from tests.conftest import DEFAULT_SETTINGS, make_player, make_settings
+from understone.engine.leveling import apply_xp, heal, rest, xp_for_level
+
+# Default curve is 100 * (n-1)*n/2 cumulative:
+#   L2 = 100, L3 = 300, L4 = 600, L5 = 1000.
+
+
+def test_xp_curve_thresholds() -> None:
+    assert xp_for_level(1, DEFAULT_SETTINGS) == 0
+    assert xp_for_level(2, DEFAULT_SETTINGS) == 100
+    assert xp_for_level(3, DEFAULT_SETTINGS) == 300
+    assert xp_for_level(4, DEFAULT_SETTINGS) == 600
+    assert xp_for_level(5, DEFAULT_SETTINGS) == 1000
+
+
+def test_just_below_threshold_does_not_level() -> None:
+    player = make_player(level=1, xp=0, hp=20, max_hp=20)
+    gains = apply_xp(player, 99, DEFAULT_SETTINGS)
+    assert gains == []
+    assert player.level == 1
+
+
+def test_exact_threshold_levels_once() -> None:
+    player = make_player(level=1, xp=0, hp=10, max_hp=20, atk=5, def_=1)
+    gains = apply_xp(player, 100, DEFAULT_SETTINGS)
+    assert len(gains) == 1
+    assert player.level == 2
+    # Growth table applied and a full heal granted on level-up.
+    assert player.max_hp == 26
+    assert player.atk == 7
+    assert player.def_ == 2
+    assert player.hp == player.max_hp
+
+
+def test_just_above_threshold_levels_once() -> None:
+    player = make_player(level=1, xp=0)
+    gains = apply_xp(player, 101, DEFAULT_SETTINGS)
+    assert len(gains) == 1
+    assert player.level == 2
+    assert player.xp == 101
+
+
+def test_single_award_can_jump_multiple_levels() -> None:
+    player = make_player(level=1, xp=0, max_hp=20, atk=5, def_=1)
+    gains = apply_xp(player, 600, DEFAULT_SETTINGS)
+    # 600 cumulative reaches level 4 (L2=100, L3=300, L4=600).
+    assert player.level == 4
+    assert [g.new_level for g in gains] == [2, 3, 4]
+    # Three levels of growth stacked.
+    assert player.max_hp == 20 + 3 * 6
+    assert player.atk == 5 + 3 * 2
+    assert player.def_ == 1 + 3 * 1
+
+
+def test_growth_table_respects_settings() -> None:
+    settings = make_settings(growth_max_hp=10, growth_atk=3, growth_def=2, xp_base=50)
+    player = make_player(level=1, xp=0, max_hp=20, atk=5, def_=1)
+    apply_xp(player, 50, settings)  # L2 at 50 with xp_base=50
+    assert player.level == 2
+    assert player.max_hp == 30
+    assert player.atk == 8
+    assert player.def_ == 3
+
+
+# ---------------------------------------------------------------------------
+# rest (inn) and heal (healer)
+# ---------------------------------------------------------------------------
+
+
+def test_rest_full_heals_and_charges() -> None:
+    player = make_player(hp=5, max_hp=20, gold=50)
+    assert rest(player, cost=15) is True
+    assert player.hp == 20
+    assert player.gold == 35
+
+
+def test_rest_refused_when_unaffordable() -> None:
+    player = make_player(hp=5, max_hp=20, gold=10)
+    assert rest(player, cost=15) is False
+    assert player.hp == 5
+    assert player.gold == 10
+
+
+def test_heal_charges_only_for_hp_restored() -> None:
+    player = make_player(hp=15, max_hp=20, gold=100)
+    result = heal(player, amount=10, cost_per_hp=2)
+    # Only 5 HP were missing.
+    assert result.healed == 5
+    assert result.cost == 10
+    assert player.hp == 20
+    assert player.gold == 90
+
+
+def test_heal_bounded_by_affordability() -> None:
+    player = make_player(hp=2, max_hp=20, gold=7)
+    result = heal(player, amount=10, cost_per_hp=2)
+    # 7 gold buys 3 HP at 2/hp.
+    assert result.healed == 3
+    assert result.cost == 6
+    assert player.hp == 5
+    assert player.gold == 1
+
+
+def test_heal_noop_when_full() -> None:
+    player = make_player(hp=20, max_hp=20, gold=100)
+    result = heal(player, amount=10, cost_per_hp=2)
+    assert result.healed == 0
+    assert result.cost == 0
+    assert player.gold == 100

examples/door-game/tests/test_mcp_integration.py

@@ -0,0 +1,288 @@
+"""End-to-end MCP integration test — the only test that touches the network.
+
+Boots the real Understone FastMCP app (backed by a temp DB) in a uvicorn
+thread, then drives it over the real streamable-HTTP wire with the real MCP
+client: initialize, list_tools (all nine door_* names), join, look. A second
+client session joins a second adventurer in the SAME process and world, and
+the first player's view then shows the '&' other-player marker — proving the
+shared-world, single-process contract over a real wire.
+
+A second test drives the read-only Watch routes that ride inside the same app:
+GET /watch (the HTML page), /watch/world.json (the static map), and
+/watch/state.json (the live snapshot) — confirming the spectator endpoints
+serve real world data alongside a working /mcp without breaking either.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import socket
+import threading
+import time
+from typing import TYPE_CHECKING, Any
+
+import httpx
+import pytest
+import uvicorn
+from mcp import ClientSession
+from mcp.client.streamable_http import streamable_http_client
+
+from understone import server as understone_server
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+PACK = str(understone_server.PACKAGED_WORLD_DIR)
+
+
+def _find_free_port() -> int:
+    s = socket.socket()
+    s.bind(("127.0.0.1", 0))
+    port = s.getsockname()[1]
+    s.close()
+    return int(port)
+
+
+def _build_server(port: int, db_path: str) -> uvicorn.Server:
+    app = understone_server.create_app(db_path, PACK)
+    config = uvicorn.Config(app, host="127.0.0.1", port=port, log_level="warning", access_log=False)
+    return uvicorn.Server(config)
+
+
+def _wait_ready(port: int, timeout: float = 5.0) -> None:
+    deadline = time.monotonic() + timeout
+    while time.monotonic() < deadline:
+        try:
+            with socket.create_connection(("127.0.0.1", port), timeout=0.5):
+                return
+        except OSError:
+            time.sleep(0.05)
+    raise TimeoutError(f"understone server at 127.0.0.1:{port} not ready after {timeout}s")
+
+
+@pytest.fixture
+def live_server(tmp_path: Path) -> Any:
+    """Boot the real Understone app in a background uvicorn thread."""
+    port = _find_free_port()
+    db_path = str(tmp_path / "wire.db")
+    server = _build_server(port, db_path)
+
+    def _run() -> None:
+        loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(loop)
+        loop.run_until_complete(server.serve())
+
+    thread = threading.Thread(target=_run, daemon=True, name="understone-itest")
+    thread.start()
+    try:
+        _wait_ready(port)
+        yield f"http://127.0.0.1:{port}/mcp"
+    finally:
+        server.should_exit = True
+        thread.join(timeout=5)
+        # create_app installed a module-level game whose Store holds an open
+        # SQLite connection; close it and clear the singleton so the next test
+        # builds its own rather than inheriting this temp DB.
+        if understone_server._GAME is not None:
+            understone_server._GAME.store.close()
+            understone_server._GAME = None
+        # FastMCP caches a StreamableHTTPSessionManager on the module-level mcp
+        # singleton and refuses a second lifespan .run() on the same instance.
+        # Reset it so each fixture instance boots a fresh session manager (the
+        # production server only ever runs one). Without this, a second
+        # fixture-using test fails on "run() can only be called once".
+        understone_server.mcp._session_manager = None
+
+
+async def _call_text(session: ClientSession, name: str, arguments: dict[str, Any]) -> str:
+    result = await session.call_tool(name, arguments)
+    chunks = [block.text for block in result.content if getattr(block, "type", None) == "text"]
+    return "\n".join(chunks)
+
+
+async def _drive(url: str) -> dict[str, Any]:
+    """Run the full client conversation and return observations."""
+    observations: dict[str, Any] = {}
+    async with (
+        streamable_http_client(url) as (read, write, _get_session_id),
+        ClientSession(read, write) as session,
+    ):
+        await session.initialize()
+
+        tools = await session.list_tools()
+        observations["tool_names"] = sorted(t.name for t in tools.tools)
+
+        observations["join_one"] = await _call_text(session, "door_join", {"player": "Brandr"})
+        observations["look_one_before"] = await _call_text(
+            session, "door_look", {"player": "Brandr"}
+        )
+
+    # A SECOND, independent session joins a second adventurer in the same world.
+    async with (
+        streamable_http_client(url) as (read, write, _get_session_id),
+        ClientSession(read, write) as session,
+    ):
+        await session.initialize()
+        # Place player two adjacent to player one so they share the view.
+        await _call_text(session, "door_join", {"player": "Sigrun"})
+        await _call_text(
+            session, "door_move", {"player": "Sigrun", "heading": "east", "distance": 1}
+        )
+
+    # Back as player one: the shared world now shows the other adventurer.
+    async with (
+        streamable_http_client(url) as (read, write, _get_session_id),
+        ClientSession(read, write) as session,
+    ):
+        await session.initialize()
+        observations["look_one_after"] = await _call_text(
+            session, "door_look", {"player": "Brandr"}
+        )
+        observations["rank"] = await _call_text(session, "door_rank", {"player": "Brandr"})
+
+    return observations
+
+
+def test_mcp_end_to_end(live_server: str) -> None:
+    obs = asyncio.run(_drive(live_server))
+
+    # All nine tools are advertised over the wire.
+    expected = {
+        "door_help",
+        "door_join",
+        "door_status",
+        "door_look",
+        "door_move",
+        "door_action",
+        "door_log",
+        "door_rank",
+        "door_bestow",
+    }
+    assert set(obs["tool_names"]) == expected
+
+    # The join + look frames are real ASCII map frames.
+    assert "@" in obs["join_one"]
+    look_before = obs["look_one_before"]
+    assert "@" in look_before
+    assert "┌" in look_before and "┐" in look_before
+
+    # Shared-world proof: after player two joins next door, player one sees '☻'.
+    assert "☻" in obs["look_one_after"]
+    # And the leaderboard lists both adventurers (one process, one world).
+    assert "Brandr" in obs["rank"]
+    assert "Sigrun" in obs["rank"]
+
+
+def _watch_base(mcp_url: str) -> str:
+    """Derive the app root (where /watch lives) from the /mcp endpoint URL."""
+    return mcp_url[: -len("/mcp")] if mcp_url.endswith("/mcp") else mcp_url
+
+
+async def _join_over_mcp(mcp_url: str, name: str) -> None:
+    """Sign one adventurer in over the real MCP wire (so state.json sees them)."""
+    async with (
+        streamable_http_client(mcp_url) as (read, write, _get_session_id),
+        ClientSession(read, write) as session,
+    ):
+        await session.initialize()
+        await _call_text(session, "door_join", {"player": name})
+
+
+def test_watch_routes_serve_world_state(live_server: str) -> None:
+    base = _watch_base(live_server)
+
+    # The MCP join writes the player into the shared world the routes read.
+    asyncio.run(_join_over_mcp(live_server, "Watcher"))
+
+    with httpx.Client(timeout=5.0) as client:
+        page = client.get(f"{base}/watch")
+        world = client.get(f"{base}/watch/world.json")
+        state = client.get(f"{base}/watch/state.json")
+
+    # The page is real HTML carrying the static masthead.
+    assert page.status_code == 200
+    assert page.headers["content-type"].startswith("text/html")
+    assert "Understone — Live Watch" in page.text
+
+    # The static world payload matches the loaded world.
+    assert world.status_code == 200
+    world_body = world.json()
+    assert world_body["width"] == 96
+    assert world_body["height"] == 48
+    assert len(world_body["glyph_rows"]) == world_body["height"]
+    assert all(len(row) == world_body["width"] for row in world_body["glyph_rows"])
+
+    # The live snapshot lists the adventurer who joined over MCP.
+    assert state.status_code == 200
+    state_body = state.json()
+    names = {p["name"] for p in state_body["players"]}
+    assert "Watcher" in names
+
+
+def test_watch_routes_coexist_with_mcp(live_server: str) -> None:
+    """The custom routes don't shadow /mcp: tool calls still work alongside them."""
+    base = _watch_base(live_server)
+
+    async def _drive_both() -> tuple[str, int]:
+        async with (
+            streamable_http_client(live_server) as (read, write, _get_session_id),
+            ClientSession(read, write) as session,
+        ):
+            await session.initialize()
+            joined = await _call_text(session, "door_join", {"player": "Coexist"})
+        with httpx.Client(timeout=5.0) as client:
+            status = client.get(f"{base}/watch/state.json").status_code
+        return joined, status
+
+    joined, watch_status = asyncio.run(_drive_both())
+    assert "@" in joined  # the MCP tool still returns a real frame
+    assert watch_status == 200  # and the watch route still answers
+
+
+def test_streamable_http_host_gate_off_localhost() -> None:
+    """A non-localhost bind must accept remote `Host` headers on /mcp.
+
+    REGRESSION: FastMCP freezes DNS-rebinding protection (a localhost-only Host
+    allowlist) at CONSTRUCTION, and ``server`` builds its FastMCP at import with
+    the default 127.0.0.1 host. A 0.0.0.0/LAN bind therefore answered TCP and
+    `/watch` but 421'd `/mcp` for every remote node ("Invalid Host header").
+    ``_serve`` drops the allowlist when bound off localhost; this pins the
+    mechanism — a default instance rejects a foreign Host, a protection-disabled
+    one accepts it (a 421 in the second case is the bug returning).
+
+    Uses fresh FastMCP instances (not the module singleton) so there is no
+    shared-state or app-cache coupling with the live-server tests above.
+    """
+    from mcp.server.fastmcp import FastMCP
+    from mcp.server.transport_security import TransportSecuritySettings
+    from starlette.testclient import TestClient
+
+    foreign = {
+        "Host": "192.168.0.239:8077",
+        "Accept": "application/json, text/event-stream",
+        "Content-Type": "application/json",
+    }
+    init = {
+        "jsonrpc": "2.0",
+        "id": 1,
+        "method": "initialize",
+        "params": {
+            "protocolVersion": "2025-03-26",
+            "capabilities": {},
+            "clientInfo": {"name": "probe", "version": "0"},
+        },
+    }
+
+    # Default (localhost-baked allowlist) — a remote Host is refused.
+    locked = FastMCP("hostgate-locked")
+    with TestClient(locked.streamable_http_app()) as client:
+        assert client.post("/mcp", headers=foreign, json=init).status_code == 421
+
+    # Protection disabled (what _serve does off localhost) — remote Host accepted.
+    opened = FastMCP("hostgate-open")
+    opened.settings.transport_security = TransportSecuritySettings(
+        enable_dns_rebinding_protection=False
+    )
+    with TestClient(opened.streamable_http_app()) as client:
+        resp = client.post("/mcp", headers=foreign, json=init)
+    assert resp.status_code != 421, f"remote Host still rejected: {resp.status_code} {resp.text}"

examples/door-game/tests/test_movement.py

@@ -0,0 +1,336 @@
+"""Movement resolution tests.
+
+Covers edge clipping on all four sides, blocking terrain, the two input
+forms (``"NNEE"`` vs heading+distance) and their equivalence, location
+entry flipping to MENU, the MAX_STEPS cap, and a stubbed always-encounter
+RNG interrupting a walk with a pending fight.
+"""
+
+from __future__ import annotations
+
+from tests.conftest import (
+    FOREST,
+    GRASS,
+    WALL,
+    WATER,
+    LocationDef,
+    Zone,
+    make_player,
+    make_world,
+)
+from understone.engine.models import Mode, WorldEvent
+from understone.engine.movement import MAX_STEPS, parse_directions, resolve_move
+from understone.engine.rng import GameRNG
+
+
+class _NeverRNG(GameRNG):
+    """An RNG whose chance() never fires (no wandering encounters)."""
+
+    def __init__(self) -> None:
+        super().__init__(seed=0)
+
+    def chance(self, probability: float) -> bool:  # noqa: ARG002
+        return False
+
+
+class _AlwaysRNG(GameRNG):
+    """An RNG whose chance() always fires (forces an encounter).
+
+    The seed still drives ``weighted_index``/``randint``, so different seeds
+    select different event rows while every encounter roll fires.
+    """
+
+    def __init__(self, seed: int = 0) -> None:
+        super().__init__(seed=seed)
+
+    def chance(self, probability: float) -> bool:  # noqa: ARG002
+        return True
+
+
+# ---------------------------------------------------------------------------
+# parse_directions
+# ---------------------------------------------------------------------------
+
+
+def test_parse_steps_string() -> None:
+    assert parse_directions("NNEE", "", 1) == ["N", "N", "E", "E"]
+
+
+def test_parse_heading_distance() -> None:
+    assert parse_directions("", "east", 3) == ["E", "E", "E"]
+
+
+def test_parse_clamps_to_max_steps() -> None:
+    assert parse_directions("NNNNNNNNNNNN", "", 1) == ["N"] * MAX_STEPS
+    assert parse_directions("", "north", 99) == ["N"] * MAX_STEPS
+
+
+def test_parse_rejects_unknown_direction() -> None:
+    try:
+        parse_directions("NQ", "", 1)
+    except ValueError as exc:
+        assert "Q" in str(exc)
+    else:  # pragma: no cover - failure path
+        raise AssertionError("expected ValueError")
+
+
+# ---------------------------------------------------------------------------
+# Edge clipping (all four sides)
+# ---------------------------------------------------------------------------
+
+
+def test_clip_north_edge() -> None:
+    world = make_world()
+    player = make_player(x=5, y=0)
+    result = resolve_move(world, player, _NeverRNG(), heading="north", distance=3)
+    assert player.y == 0
+    assert result.steps_taken == 0
+    assert result.blocked
+
+
+def test_clip_south_edge() -> None:
+    world = make_world()
+    player = make_player(x=5, y=10)
+    result = resolve_move(world, player, _NeverRNG(), heading="south", distance=3)
+    assert player.y == 10
+    assert result.blocked
+
+
+def test_clip_west_edge() -> None:
+    world = make_world()
+    player = make_player(x=0, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="west", distance=3)
+    assert player.x == 0
+    assert result.blocked
+
+
+def test_clip_east_edge() -> None:
+    world = make_world()
+    player = make_player(x=10, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="east", distance=3)
+    assert player.x == 10
+    assert result.blocked
+
+
+def test_partial_move_then_clip() -> None:
+    world = make_world()
+    player = make_player(x=8, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="east", distance=5)
+    # 8 -> 9 -> 10, then edge.
+    assert player.x == 10
+    assert result.steps_taken == 2
+    assert result.blocked
+
+
+# ---------------------------------------------------------------------------
+# Blocking terrain
+# ---------------------------------------------------------------------------
+
+
+def test_blocked_by_wall() -> None:
+    grid = [[GRASS for _ in range(11)] for _ in range(11)]
+    grid[5][6] = WALL
+    world = make_world(grid=grid)
+    player = make_player(x=5, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="east", distance=2)
+    assert player.x == 5
+    assert result.blocked
+    assert "wall" in result.blocked_reason
+
+
+def test_blocked_by_water() -> None:
+    grid = [[GRASS for _ in range(11)] for _ in range(11)]
+    grid[4][5] = WATER
+    world = make_world(grid=grid)
+    player = make_player(x=5, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="north", distance=2)
+    assert player.y == 5
+    assert result.blocked
+    assert "water" in result.blocked_reason
+
+
+# ---------------------------------------------------------------------------
+# Input-form equivalence and direction correctness
+# ---------------------------------------------------------------------------
+
+
+def test_nnee_lands_at_expected_cell() -> None:
+    world = make_world()
+    player = make_player(x=5, y=5)
+    resolve_move(world, player, _NeverRNG(), steps="NNEE")
+    # Two north (y-2), two east (x+2).
+    assert (player.x, player.y) == (7, 3)
+
+
+def test_heading_equivalent_to_steps() -> None:
+    world_a = make_world()
+    player_a = make_player(x=5, y=5)
+    resolve_move(world_a, player_a, _NeverRNG(), steps="EEE")
+
+    world_b = make_world()
+    player_b = make_player(x=5, y=5)
+    resolve_move(world_b, player_b, _NeverRNG(), heading="east", distance=3)
+
+    assert (player_a.x, player_a.y) == (player_b.x, player_b.y)
+
+
+def test_max_steps_truncates_long_walk() -> None:
+    world = make_world(width=40, height=11)
+    player = make_player(x=0, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="east", distance=99)
+    assert result.steps_taken == MAX_STEPS
+    assert player.x == MAX_STEPS
+
+
+# ---------------------------------------------------------------------------
+# Location entry flips to MENU
+# ---------------------------------------------------------------------------
+
+
+def test_entering_location_flips_menu_mode() -> None:
+    loc = LocationDef(
+        key="inn",
+        kind="inn",
+        name="The Sleeping Drake",
+        x=7,
+        y=5,
+        glyph="I",
+        color="town",
+        actions=("rest", "leave"),
+    )
+    world = make_world(locations=[loc])
+    player = make_player(x=5, y=5)
+    result = resolve_move(world, player, _NeverRNG(), heading="east", distance=4)
+    assert player.mode is Mode.MENU
+    assert player.at_location == "inn"
+    assert result.entered_location == "inn"
+    # Stopped on the door at x=7 even though distance asked for 4.
+    assert (player.x, player.y) == (7, 5)
+
+
+# ---------------------------------------------------------------------------
+# Encounter interrupt
+# ---------------------------------------------------------------------------
+
+
+def test_always_encounter_stops_with_pending_fight() -> None:
+    grid = [[FOREST for _ in range(11)] for _ in range(11)]
+    zone = Zone(key="wood", x0=0, y0=0, x1=10, y1=10, tier_lo=1, tier_hi=2)
+    world = make_world(grid=grid, zones=[zone])
+    player = make_player(x=5, y=5)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=5)
+    assert result.pending_fight == (1, 2)
+    # The encounter fires on the first entered cell.
+    assert result.steps_taken == 1
+    assert player.x == 6
+
+
+def test_no_zone_means_no_encounter() -> None:
+    grid = [[FOREST for _ in range(11)] for _ in range(11)]
+    world = make_world(grid=grid, zones=[])
+    player = make_player(x=5, y=5)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=3)
+    assert result.pending_fight is None
+    assert result.steps_taken == 3
+
+
+# ---------------------------------------------------------------------------
+# Weighted non-combat overworld events (v0.2)
+# ---------------------------------------------------------------------------
+
+
+def _event_world(*events: WorldEvent) -> object:
+    """An all-forest, fully-zoned world carrying a crafted event table."""
+    grid = [[FOREST for _ in range(11)] for _ in range(11)]
+    zone = Zone(key="wood", x0=0, y0=0, x1=10, y1=10, tier_lo=1, tier_hi=2)
+    return make_world(grid=grid, zones=[zone], events=list(events))
+
+
+def test_event_fight_stops_the_walk() -> None:
+    """A fight-kind event sets pending_fight and halts the walk like v0.1."""
+    world = _event_world(WorldEvent("fight", 1, "", 0, 0))
+    player = make_player(x=5, y=5)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=5)
+    assert result.pending_fight == (1, 2)
+    assert result.event is None
+    assert result.steps_taken == 1  # stopped on the first triggering cell
+
+
+def test_event_gold_credits_and_continues() -> None:
+    """A gold event credits the rolled amount and does NOT stop the walk."""
+    world = _event_world(WorldEvent("gold", 1, "a coin-purse", 5, 5))
+    player = make_player(x=5, y=5, gold=10)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=3)
+    assert result.event is not None
+    assert result.event.kind == "gold"
+    assert result.event.amount == 5  # min == max == 5, so deterministic
+    assert player.gold == 15
+    assert result.pending_fight is None
+    assert result.steps_taken == 3  # the walk ran to completion
+
+
+def test_event_heal_caps_at_max_hp() -> None:
+    """A heal event never overfills: hp is clamped to max_hp."""
+    world = _event_world(WorldEvent("heal", 1, "a spring", 50, 50))
+    player = make_player(x=5, y=5, hp=18, max_hp=20)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=1)
+    assert player.hp == 20  # +50 requested, capped at the 2 missing
+    assert result.event is not None and result.event.amount == 2
+
+
+def test_event_trap_floors_hp_at_one_and_spares_gold() -> None:
+    """A trap event never kills (floors at 1 HP) and never touches gold."""
+    world = _event_world(WorldEvent("trap", 1, "old briars", 500, 500))
+    player = make_player(x=5, y=5, hp=10, max_hp=20, gold=42)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=1)
+    assert player.hp == 1  # huge trap, but floored
+    assert player.gold == 42  # gold untouched
+    assert result.event is not None and result.event.amount == 9  # only 9 could be taken
+
+
+def test_event_lore_mutates_nothing() -> None:
+    """A lore event changes no state and reports a zero amount."""
+    world = _event_world(WorldEvent("lore", 1, "an old waystone", 0, 0))
+    player = make_player(x=5, y=5, hp=15, max_hp=20, gold=7)
+    before = (player.hp, player.gold)
+    result = resolve_move(world, player, _AlwaysRNG(), heading="east", distance=2)
+    assert (player.hp, player.gold) == before
+    assert result.event is not None and result.event.kind == "lore"
+    assert result.event.amount == 0
+    assert result.steps_taken == 2
+
+
+def test_at_most_one_event_per_walk() -> None:
+    """Once any event fires, no further cells roll for the rest of the walk.
+
+    Two distinct gold rolls would credit 2 gold (1 each); a single fired event
+    credits exactly 1, proving the walk stops rolling after the first trigger.
+    """
+    world = _event_world(WorldEvent("gold", 1, "a coin", 1, 1))
+    player = make_player(x=5, y=5, gold=0)
+    resolve_move(world, player, _AlwaysRNG(), heading="east", distance=5)
+    assert player.gold == 1  # exactly one event, not five
+
+
+def test_each_event_kind_reachable_with_crafted_table() -> None:
+    """Equal weights make every kind in a crafted table reachable from movement."""
+    table = [
+        WorldEvent("fight", 1, "", 0, 0),
+        WorldEvent("gold", 1, "g", 1, 1),
+        WorldEvent("heal", 1, "h", 1, 1),
+        WorldEvent("trap", 1, "t", 1, 1),
+        WorldEvent("lore", 1, "l", 0, 0),
+    ]
+    zone = Zone(key="wood", x0=0, y0=0, x1=0, y1=0, tier_lo=1, tier_hi=2)
+    grid = [[FOREST for _ in range(11)] for _ in range(11)]
+    world = make_world(grid=grid, zones=[zone], events=table)
+
+    seen: set[str] = set()
+    for seed in range(60):
+        player = make_player(x=0, y=1, hp=10, max_hp=20)  # one step north into the zone cell
+        result = resolve_move(world, player, _AlwaysRNG(seed), steps="N")
+        if result.pending_fight is not None:
+            seen.add("fight")
+        elif result.event is not None:
+            seen.add(result.event.kind)
+    assert seen == {"fight", "gold", "heal", "trap", "lore"}

examples/door-game/tests/test_package.py

@@ -0,0 +1,9 @@
+"""Smoke test for the packaging skeleton."""
+
+from __future__ import annotations
+
+import understone
+
+
+def test_version_present() -> None:
+    assert understone.__version__ == "0.10.0"

examples/door-game/tests/test_persistence.py

@@ -0,0 +1,269 @@
+"""SQLite persistence tests.
+
+Covers idempotent schema init, a full player round-trip through every
+column (including ``def_``, ``turn_day``, ``log_cursor`` and the bestow
+fields), event append with cursor-based catch-up, leaderboard tie-breaks,
+and that WAL journaling is active.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from tests.conftest import make_player
+from understone.engine.log import since
+from understone.engine.models import Mode
+from understone.persistence import Store
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+
+def _store(tmp_path: Path) -> Store:
+    return Store(tmp_path / "understone.db")
+
+
+def test_schema_init_is_idempotent(tmp_path: Path) -> None:
+    db = tmp_path / "understone.db"
+    Store(db).close()
+    # Re-opening the same file must not error or duplicate schema.
+    second = Store(db)
+    assert second.get_meta("schema_version") == "1"
+    second.close()
+
+
+def test_wal_mode_active(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    assert store.journal_mode().lower() == "wal"
+    store.close()
+
+
+def test_player_round_trip_all_columns(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    player = make_player(
+        name="Brandr",
+        x=12,
+        y=7,
+        hp=18,
+        max_hp=26,
+        level=3,
+        xp=305,
+        gold=88,
+        atk=9,
+        def_=4,
+        weapon_id="short_sword",
+        armor_id="leather_armor",
+        turns_left=6,
+        turn_day=739_400,
+        mode=Mode.MENU,
+        at_location="inn",
+        log_cursor=42,
+        bestow_spent=15,
+        bestow_day=739_400,
+        posts_sent=3,
+        post_day=739_400,
+        gambles=2,
+        gamble_day=739_400,
+        banked=420,
+    )
+    store.upsert_player(player)
+    store.commit()
+    store.close()
+
+    reopened = _store(tmp_path)
+    players, _ = reopened.load_all()
+    loaded = players["Brandr"]
+    assert loaded == player
+    assert loaded.banked == 420
+    # Spot-check the fields most prone to silent drop.
+    assert loaded.def_ == 4
+    assert loaded.turn_day == 739_400
+    assert loaded.log_cursor == 42
+    assert loaded.bestow_spent == 15
+    assert loaded.bestow_day == 739_400
+    assert loaded.mode is Mode.MENU
+    # The v0.5 social columns survive the round-trip too.
+    assert loaded.posts_sent == 3
+    assert loaded.post_day == 739_400
+    assert loaded.gambles == 2
+    assert loaded.gamble_day == 739_400
+    reopened.close()
+
+
+def test_event_target_round_trips(tmp_path: Path) -> None:
+    """A targeted (private) event keeps its target across a reopen; public is ''."""
+    store = _store(tmp_path)
+    pub = store.insert_event("t1", "Brandr", "join", "set out")
+    priv = store.insert_event("t2", "Sigrun", "ambushed", "robbed in your sleep", "Brandr")
+    store.commit()
+    store.close()
+
+    reopened = _store(tmp_path)
+    _, events = reopened.load_all()
+    by_id = {e.event_id: e for e in events}
+    assert by_id[pub].target == ""  # public stays empty
+    assert by_id[priv].target == "Brandr"  # private keeps its recipient
+    reopened.close()
+
+
+def test_ambush_table_per_day_uniqueness(tmp_path: Path) -> None:
+    """The ambushes PK is (attacker, target, day): one row per pair per day."""
+    store = _store(tmp_path)
+    day = 739_400
+    assert store.has_ambushed("Brandr", "Sigrun", day) is False
+    store.record_ambush("Brandr", "Sigrun", day)
+    store.commit()
+    assert store.has_ambushed("Brandr", "Sigrun", day) is True
+    # A second record for the same pair/day is a no-op (INSERT OR IGNORE):
+    # the duplicate must not raise and must not add a row.
+    store.record_ambush("Brandr", "Sigrun", day)
+    store.commit()
+    rows = store._conn.execute(
+        "SELECT COUNT(*) AS n FROM ambushes WHERE attacker=? AND target=? AND day=?",
+        ("Brandr", "Sigrun", day),
+    ).fetchone()
+    assert rows["n"] == 1
+    # A new day is a fresh attempt; the old day stays recorded.
+    assert store.has_ambushed("Brandr", "Sigrun", day + 1) is False
+    store.record_ambush("Brandr", "Sigrun", day + 1)
+    store.commit()
+    assert store.has_ambushed("Brandr", "Sigrun", day) is True
+    assert store.has_ambushed("Brandr", "Sigrun", day + 1) is True
+    store.close()
+
+
+def test_upsert_updates_existing_row(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    player = make_player(name="Sigrun", gold=10)
+    store.upsert_player(player)
+    store.commit()
+    player.gold = 999
+    store.upsert_player(player)
+    store.commit()
+    store.close()
+
+    reopened = _store(tmp_path)
+    players, _ = reopened.load_all()
+    assert players["Sigrun"].gold == 999
+    assert len(players) == 1
+    reopened.close()
+
+
+def test_event_append_and_since_cursor(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    id1 = store.insert_event("t1", "Brandr", "fight", "slew a rat")
+    id2 = store.insert_event("t2", "Sigrun", "bestow", "blessed with gold")
+    store.commit()
+    store.close()
+
+    reopened = _store(tmp_path)
+    _, events = reopened.load_all()
+    assert [e.event_id for e in events] == [id1, id2]
+
+    # Catch up from a cursor before both, then advance past the first.
+    fresh, cursor = since(events, 0)
+    assert len(fresh) == 2
+    assert cursor == id2
+
+    after_first, cursor2 = since(events, id1)
+    assert [e.event_id for e in after_first] == [id2]
+    assert cursor2 == id2
+
+    nothing, cursor3 = since(events, id2)
+    assert nothing == []
+    assert cursor3 == id2
+    reopened.close()
+
+
+def test_top_ranks_tie_breaks(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    # Same level: higher XP ranks first; equal XP breaks by name ascending.
+    store.upsert_player(make_player(name="Carol", level=5, xp=1200, gold=10))
+    store.upsert_player(make_player(name="Alice", level=5, xp=1500, gold=10))
+    store.upsert_player(make_player(name="Bob", level=5, xp=1500, gold=10))
+    store.upsert_player(make_player(name="Dave", level=4, xp=9999, gold=10))
+    store.commit()
+
+    ranks = store.top_ranks(limit=10)
+    assert [r.name for r in ranks] == ["Alice", "Bob", "Carol", "Dave"]
+    store.close()
+
+
+def test_top_ranks_honours_limit(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    for i in range(15):
+        store.upsert_player(make_player(name=f"P{i:02d}", level=i, xp=i * 10))
+    store.commit()
+    ranks = store.top_ranks(limit=10)
+    assert len(ranks) == 10
+    # Highest level first.
+    assert ranks[0].name == "P14"
+    store.close()
+
+
+def test_meta_round_trip(tmp_path: Path) -> None:
+    store = _store(tmp_path)
+    store.set_meta("world_name", "The Vale of Understone")
+    assert store.get_meta("world_name") == "The Vale of Understone"
+    assert store.get_meta("missing") is None
+    store.close()
+
+
+def test_retention_columns_round_trip(tmp_path: Path) -> None:
+    """The retention columns survive a reopen: depth, the v0.10 stack-encoded
+    satchel, the two forged plusses, and the v0.10 banked vault gold."""
+    store = _store(tmp_path)
+    player = make_player(
+        name="Delver",
+        deepest_rung=2,
+        satchel="minor_potion:3,iron_ore:5",  # v0.10 "id:qty" stack encoding
+        weapon_plus=2,
+        armor_plus=1,
+        banked=300,
+    )
+    store.upsert_player(player)
+    store.commit()
+    store.close()
+
+    reopened = _store(tmp_path)
+    players, _ = reopened.load_all()
+    loaded = players["Delver"]
+    assert loaded == player  # full equality across every column
+    assert loaded.deepest_rung == 2
+    assert loaded.satchel == "minor_potion:3,iron_ore:5"
+    assert loaded.weapon_plus == 2
+    assert loaded.armor_plus == 1
+    assert loaded.banked == 300
+    reopened.close()
+
+
+def test_v0_7_depth_columns_default_for_legacy_rows(tmp_path: Path) -> None:
+    """A row written without the new columns loads them at their defaults.
+
+    The schema mutates in place (no migration, stamp stays 1), so the new
+    columns carry DB-side defaults: a pre-v0.7 player row (inserted with the
+    legacy column set) must read back deepest_rung 0, an empty satchel, and
+    zero plusses rather than erroring.
+    """
+    store = _store(tmp_path)
+    store._conn.execute(
+        "INSERT INTO players "
+        "(name, x, y, hp, max_hp, level, xp, gold, atk, def_, weapon_id, armor_id, "
+        " turns_left, turn_day, mode, at_location, created_at, last_seen, log_cursor, "
+        " bestow_spent, bestow_day) "
+        "VALUES ('Old', 5, 5, 20, 20, 1, 0, 20, 5, 1, 'rusty_dagger', 'cloth_tunic', "
+        " 10, 0, 'tile', '', 't0', 't0', 0, 0, 0)",
+    )
+    store.commit()
+    store.close()
+
+    reopened = _store(tmp_path)
+    players, _ = reopened.load_all()
+    old = players["Old"]
+    assert old.deepest_rung == 0
+    assert old.satchel == ""
+    assert old.weapon_plus == 0
+    assert old.armor_plus == 0
+    assert old.banked == 0  # the v0.10 vault column defaults too
+    assert reopened.get_meta("schema_version") == "1"  # stamp unchanged
+    reopened.close()

examples/door-game/tests/test_rng.py

@@ -0,0 +1,47 @@
+"""GameRNG tests — the deterministic randomness seam.
+
+Covers the v0.2 ``weighted_index`` helper: that a fixed seed reproduces the
+same stream, that the cumulative-sum mapping honours the weights' proportions,
+and that every index of a crafted table is reachable.
+"""
+
+from __future__ import annotations
+
+from collections import Counter
+
+from understone.engine.rng import GameRNG
+
+
+def test_weighted_index_is_deterministic_under_seed() -> None:
+    """Two RNGs at the same seed yield the identical weighted-index stream."""
+    weights = [55, 8, 7, 5, 5, 5, 5, 3, 3, 4]
+    a = GameRNG(seed=2026)
+    b = GameRNG(seed=2026)
+    draws_a = [a.weighted_index(weights) for _ in range(50)]
+    draws_b = [b.weighted_index(weights) for _ in range(50)]
+    assert draws_a == draws_b
+
+
+def test_weighted_index_every_index_reachable() -> None:
+    """With equal weights, a crafted table sees every index appear."""
+    weights = [1, 1, 1, 1, 1]
+    rng = GameRNG(seed=7)
+    seen = {rng.weighted_index(weights) for _ in range(500)}
+    assert seen == set(range(len(weights)))
+
+
+def test_weighted_index_single_entry_always_zero() -> None:
+    """A one-row table can only ever pick index 0."""
+    rng = GameRNG(seed=1)
+    assert all(rng.weighted_index([9]) == 0 for _ in range(20))
+
+
+def test_weighted_index_respects_proportions() -> None:
+    """A heavily-weighted index dominates the empirical distribution."""
+    weights = [90, 5, 5]
+    rng = GameRNG(seed=99)
+    counts = Counter(rng.weighted_index(weights) for _ in range(4000))
+    # Index 0 carries 90% of the mass; it must be by far the most common.
+    assert counts[0] > counts[1] + counts[2]
+    # And the rare indices still occur (no off-by-one swallowing the tail).
+    assert counts[1] > 0 and counts[2] > 0

examples/door-game/tests/test_satchel.py

@@ -0,0 +1,63 @@
+"""The satchel "id:qty" wire codec (understone.engine.satchel).
+
+Pins the single-source codec the game façade, the Watch payload, and the
+balance simulator all decode through. The format is comma-joined ``id:qty``
+stacks; this proves a clean round-trip, the defensive bare-id => qty-1 rule, the
+malformed/zero/empty fragments that are skipped, and that the encoder never
+emits a zero-or-negative stack.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from understone.engine.satchel import decode_satchel, encode_satchel
+
+
+def test_round_trips_id_qty_stacks() -> None:
+    """The canonical "id:qty,id:qty" data decodes and re-encodes unchanged."""
+    encoded = "minor_potion:3,iron_ore:5"
+    stacks = decode_satchel(encoded)
+    assert stacks == [("minor_potion", 3), ("iron_ore", 5)]
+    assert encode_satchel(stacks) == encoded
+
+
+def test_bare_id_decodes_as_qty_one() -> None:
+    """A colonless chunk is a single item (defensive — never silently dropped)."""
+    assert decode_satchel("minor_potion") == [("minor_potion", 1)]
+    # Mixed with a normal stack, order preserved.
+    assert decode_satchel("minor_potion,iron_ore:5") == [
+        ("minor_potion", 1),
+        ("iron_ore", 5),
+    ]
+
+
+@pytest.mark.parametrize(
+    ("encoded", "reason"),
+    [
+        ("id:0", "zero quantity"),
+        ("id:-1", "negative quantity"),
+        ("id:abc", "non-integer quantity"),
+        (":5", "empty id"),
+        ("", "empty string"),
+        ("minor_potion:3,", "trailing comma yields an empty chunk"),
+        (",minor_potion:3", "leading comma yields an empty chunk"),
+    ],
+)
+def test_skips_malformed_or_zero_fragments(encoded: str, reason: str) -> None:
+    """A present-but-invalid or non-positive fragment is skipped; valid ones survive."""
+    stacks = decode_satchel(encoded)
+    assert all(item_id and qty > 0 for item_id, qty in stacks), reason
+    # The only valid stack in the trailing/leading-comma cases is the potion.
+    if "minor_potion:3" in encoded:
+        assert stacks == [("minor_potion", 3)]
+    else:
+        assert stacks == []
+
+
+def test_encode_drops_non_positive_stacks() -> None:
+    """The encoder never emits "id:0" or a negative quantity."""
+    assert encode_satchel([("minor_potion", 0)]) == ""
+    assert encode_satchel([("minor_potion", -2)]) == ""
+    assert encode_satchel([("minor_potion", 2), ("iron_ore", 0)]) == "minor_potion:2"
+    assert encode_satchel([]) == ""

examples/door-game/tests/test_screen.py

@@ -0,0 +1,169 @@
+"""Screen-layer tests: viewport maths, frame rendering, menu rendering.
+
+Golden discipline: the golden files under ``tests/golden`` are authored by
+hand (correct borders/centring, eyeballed) and are NOT machine-dumped
+renderer output. Every golden comparison is paired with structural asserts
+that hold independent of the exact golden bytes, so a renderer regression
+that happens to match a stale golden still trips a structural check.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from understone.screen.grid import Cell, CellGrid
+from understone.screen.menus import render_menu
+from understone.screen.palette import Color
+from understone.screen.text_renderer import render_frame
+from understone.screen.viewport import compute_window
+
+GOLDEN = Path(__file__).parent / "golden"
+
+
+# ---------------------------------------------------------------------------
+# viewport.compute_window
+# ---------------------------------------------------------------------------
+
+
+def test_window_centers_when_interior() -> None:
+    # 100x100 map, 48x16 view, focus at (50, 50): centred.
+    x0, y0 = compute_window(100, 100, 48, 16, 50, 50)
+    assert x0 == 50 - 48 // 2
+    assert y0 == 50 - 16 // 2
+
+
+def test_window_clamps_nw_corner() -> None:
+    x0, y0 = compute_window(100, 100, 48, 16, 0, 0)
+    assert (x0, y0) == (0, 0)
+
+
+def test_window_clamps_ne_corner() -> None:
+    x0, y0 = compute_window(100, 100, 48, 16, 99, 0)
+    assert x0 == 100 - 48
+    assert y0 == 0
+
+
+def test_window_clamps_sw_corner() -> None:
+    x0, y0 = compute_window(100, 100, 48, 16, 0, 99)
+    assert x0 == 0
+    assert y0 == 100 - 16
+
+
+def test_window_clamps_se_corner() -> None:
+    x0, y0 = compute_window(100, 100, 48, 16, 99, 99)
+    assert x0 == 100 - 48
+    assert y0 == 100 - 16
+
+
+def test_window_view_larger_than_map_pins_origin() -> None:
+    x0, y0 = compute_window(10, 8, 48, 16, 5, 4)
+    assert (x0, y0) == (0, 0)
+
+
+# ---------------------------------------------------------------------------
+# Shared small-grid builders for the golden frames
+# ---------------------------------------------------------------------------
+
+_FLOOR = Cell(".", Color.FLOOR)
+_PLAYER = Cell("@", Color.PLAYER)
+
+
+def _floor_grid(rows: int, cols: int) -> CellGrid:
+    grid = CellGrid(rows, cols)
+    for r in range(rows):
+        for c in range(cols):
+            grid.set(r, c, _FLOOR)
+    return grid
+
+
+def _spawn_grid() -> CellGrid:
+    """9x5 floor with the player centred at (row 2, col 4)."""
+    grid = _floor_grid(5, 9)
+    grid.set(2, 4, _PLAYER)
+    return grid
+
+
+def _edge_nw_grid() -> CellGrid:
+    """9x5 floor with the player pinned to the NW corner (row 0, col 0)."""
+    grid = _floor_grid(5, 9)
+    grid.set(0, 0, _PLAYER)
+    return grid
+
+
+# ---------------------------------------------------------------------------
+# text_renderer.render_frame
+# ---------------------------------------------------------------------------
+
+
+def test_render_frame_matches_golden_spawn() -> None:
+    frame = render_frame(_spawn_grid(), title="Vale", status="[ status ]")
+    expected = (GOLDEN / "viewport_spawn.txt").read_text(encoding="utf-8")
+    assert frame == expected.rstrip("\n")
+
+
+def test_render_frame_matches_golden_edge_nw() -> None:
+    frame = render_frame(_edge_nw_grid(), title="Vale", status="[ status ]")
+    expected = (GOLDEN / "viewport_edge_nw.txt").read_text(encoding="utf-8")
+    assert frame == expected.rstrip("\n")
+
+
+def test_render_frame_structural_invariants() -> None:
+    frame = render_frame(_spawn_grid(), title="Vale", status="[ status ]")
+    lines = frame.split("\n")
+    # Top border, 5 grid rows, bottom border, status = 8 lines.
+    assert len(lines) == 8
+    # Title substring lives in the top border.
+    assert "Vale" in lines[0]
+    # Uniform width across the box (top border through bottom border).
+    box_lines = lines[:-1]
+    widths = {len(line) for line in box_lines}
+    assert len(widths) == 1, f"box rows ragged: {widths}"
+    # Exactly one '@' and it sits at the centre column of the interior.
+    body = lines[1:-2]
+    at_positions = [(r, line.index("@")) for r, line in enumerate(body) if "@" in line]
+    assert len(at_positions) == 1
+    _, col = at_positions[0]
+    # Interior centre: 1 (left border) + cols//2 = 1 + 4 = 5.
+    assert col == 1 + 9 // 2
+    # Status line is preserved verbatim as the last line.
+    assert lines[-1] == "[ status ]"
+
+
+def test_render_frame_under_size_budget() -> None:
+    grid = _floor_grid(16, 48)
+    grid.set(8, 24, _PLAYER)
+    frame = render_frame(grid, title="The Vale of Understone", status="[ a long status line here ]")
+    assert len(frame) < 2048
+
+
+# ---------------------------------------------------------------------------
+# menus.render_menu
+# ---------------------------------------------------------------------------
+
+
+def test_render_menu_matches_golden_inn() -> None:
+    menu = render_menu(
+        "The Sleeping Drake",
+        ["A warm hearth crackles.", "A bed costs 15 gold."],
+        ["(R)est", "(L)eave"],
+        "[ status ]",
+    )
+    expected = (GOLDEN / "menu_inn.txt").read_text(encoding="utf-8")
+    assert menu == expected.rstrip("\n")
+
+
+def test_render_menu_structural_invariants() -> None:
+    menu = render_menu(
+        "The Sleeping Drake",
+        ["A warm hearth crackles.", "A bed costs 15 gold."],
+        ["(R)est", "(L)eave"],
+        "[ status ]",
+    )
+    lines = menu.split("\n")
+    assert "The Sleeping Drake" in lines[0]
+    assert lines[-1] == "[ status ]"
+    box = lines[:-1]
+    widths = {len(line) for line in box}
+    assert len(widths) == 1, f"menu box ragged: {widths}"
+    # Option line is present inside the body.
+    assert any("(R)est" in line and "(L)eave" in line for line in lines)

examples/door-game/tests/test_sim.py

@@ -0,0 +1,306 @@
+"""Tests for the balance instrument (the greedy bot simulator).
+
+These run the REAL game façade end-to-end, so they double as the fiercest
+integration test in the suite: determinism (same inputs → identical report),
+that the greedy bot makes genuine progress over a Vale run, that its realized
+fight share lands in a sane band, that a multi-seed sweep aggregates and the
+report renders — and the single best end-to-end assertion, that a short seed
+sweep actually SLAYS THE WYRM, proving the whole v0.1–v0.7 loop is winnable by
+an unclever bot.
+"""
+
+from __future__ import annotations
+
+from io import StringIO
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+from understone import sim
+from understone.engine.models import LocationDef, Mode, Zone
+from understone.engine.rng import GameRNG
+from understone.game import Game
+from understone.persistence import Store
+from understone.sim import BalanceReport, simulate
+
+from .conftest import make_monster, make_world
+
+if TYPE_CHECKING:
+    import pytest
+
+PACK = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+
+# ---------------------------------------------------------------------------
+# determinism
+# ---------------------------------------------------------------------------
+
+
+def test_same_inputs_give_identical_report() -> None:
+    """Same (pack, days, seed) → byte-identical BalanceReport (frozen + seeded)."""
+    a = simulate(PACK, 20, 5)
+    b = simulate(PACK, 20, 5)
+    assert a == b
+    assert isinstance(a, BalanceReport)
+
+
+def test_different_seeds_diverge() -> None:
+    """Different seeds produce different runs (the RNG actually threads through)."""
+    a = simulate(PACK, 20, 1)
+    b = simulate(PACK, 20, 2)
+    # The runs are not identical (some headline measure differs).
+    assert (a.fights_fought, a.total_gold_earned, a.day_of_first_wyrm_kill) != (
+        b.fights_fought,
+        b.total_gold_earned,
+        b.day_of_first_wyrm_kill,
+    )
+
+
+# ---------------------------------------------------------------------------
+# progress
+# ---------------------------------------------------------------------------
+
+
+def test_bot_makes_progress_over_thirty_days() -> None:
+    """A 30-day Vale run climbs past level 1 and actually fights."""
+    r = simulate(PACK, 30, 1)
+    assert r.final_level > 1
+    assert r.fights_fought > 0
+    assert r.total_gold_earned > 0
+    # It also plumbs the deep — the rung ladder is reachable for a geared bot.
+    assert r.rungs_cleared > 0
+
+
+def test_realized_fight_share_in_sane_band() -> None:
+    """The bot's fight share is a real fraction and forest-fight dominant.
+
+    A greedy XP grinder spends most of its turns fighting the wood (the rest are
+    the handful of descents and the Wyrm bout), so the share is high — but it is
+    a genuine fraction in (0, 1], never a degenerate 0 or a value out of range.
+    """
+    r = simulate(PACK, 30, 3)
+    assert 0.0 < r.realized_fight_share <= 1.0
+    # Fights dominate the turn-spend, but descents/challenges exist too, so the
+    # share is below a hard 1.0 floor only loosely — assert the sane half-band.
+    assert r.realized_fight_share >= 0.5
+
+
+# ---------------------------------------------------------------------------
+# reporting & sweep
+# ---------------------------------------------------------------------------
+
+
+def test_report_renders_without_crashing() -> None:
+    r = simulate(PACK, 15, 1)
+    text = sim._render_report("The Vale of Understone", r)
+    assert "greedy bot" in text
+    assert "final level" in text
+    assert "Wyrm slain" in text
+
+
+def test_cli_simulate_single_seed_renders(tmp_path: Path) -> None:
+    out = StringIO()
+    rc = sim.cli_simulate(PACK, 15, 1, out=out)
+    assert rc == 0
+    assert "The Vale of Understone" in out.getvalue()
+    assert "fight share" in out.getvalue()
+
+
+def test_cli_simulate_sweep_aggregates() -> None:
+    """A --seeds sweep prints per-seed lines plus an aggregate with spreads."""
+    out = StringIO()
+    rc = sim.cli_simulate(PACK, 20, 1, out=out, seeds=3)
+    assert rc == 0
+    text = out.getvalue()
+    assert "3 seeds" in text
+    assert "aggregate" in text
+    # Per-seed lines for each of the three seeds.
+    for seed in (1, 2, 3):
+        assert f"seed {seed:>3}" in text or f"seed   {seed}" in text
+    # The aggregate carries a mean [min..max] spread.
+    assert "[" in text and "]" in text
+
+
+def test_sweep_reports_are_each_deterministic() -> None:
+    """Each seed in a sweep is independently reproducible by single simulate."""
+    seed = 4
+    swept = simulate(PACK, 20, seed)
+    again = simulate(PACK, 20, seed)
+    assert swept == again
+
+
+# ---------------------------------------------------------------------------
+# the load-bearing assertion: the world is winnable
+# ---------------------------------------------------------------------------
+
+
+def test_greedy_bot_slays_the_wyrm() -> None:
+    """The single best end-to-end check: a short seed sweep KILLS THE WYRM.
+
+    If a greedy, unclever bot can take the Wyrm Below playing through the real
+    façade, then the whole authored loop — movement, the zone-banded forest, the
+    economy, the rung ladder, the satchel death-save, the forge, and the endgame
+    gate — composes into a *winnable* game. A run that ever stops winning trips
+    here. A small sweep (not one lucky seed) so the proof is robust.
+    """
+    reports = [simulate(PACK, 40, seed) for seed in (1, 2, 3)]
+    kills = [r for r in reports if r.wyrm_killed]
+    assert kills, "the greedy bot never slew the Wyrm across the seed sweep"
+    # Every kill records the day it first happened, within the run window.
+    for r in kills:
+        assert r.day_of_first_wyrm_kill is not None
+        assert 1 <= r.day_of_first_wyrm_kill <= 40
+
+
+# ---------------------------------------------------------------------------
+# the bundled ALTERNATE world: The Cinder Wastes (LLM-authored from the manual)
+#
+# The Vale assertions above are the primary proof. These mirror them against the
+# real bundled second world, so the dogfood pack — authored cold from AUTHORING.md
+# — is held to the same bar: the bot must make genuine progress through it, and a
+# short seed sweep must actually slay its Magma Wyrm. If the authored world ever
+# stops being winnable, this trips.
+# ---------------------------------------------------------------------------
+
+CINDER = Path(__file__).resolve().parents[1] / "understone" / "world" / "packs" / "cinder-wastes"
+
+
+def test_cinder_wastes_bot_makes_progress() -> None:
+    """A short Cinder Wastes run climbs past level 1 and genuinely plays.
+
+    Fifteen days lands before the bot's first Wyrm kill (~day 24), so the level
+    is still climbing rather than reset post-win — a stable "the world plays"
+    signal across the durable measures (level, fights, gold, the rung ladder).
+    """
+    r = simulate(CINDER, 15, 1)
+    assert r.final_level > 1
+    assert r.fights_fought > 0
+    assert r.total_gold_earned > 0
+    assert r.rungs_cleared > 0  # the caldera rung ladder is reachable
+
+
+def test_cinder_wastes_is_winnable() -> None:
+    """The dogfood proof: a greedy bot SLAYS THE MAGMA WYRM in the authored world.
+
+    The Cinder Wastes was written by an LLM working only from AUTHORING.md and
+    the validator. This is the end-to-end demonstration that the manual plus the
+    loader produce not merely a *valid* pack but a *playable-to-victory* one — a
+    short seed sweep takes the Magma Wyrm. (It is harder than the Vale: the kill
+    lands later, so the window is wider than the Vale's.)
+    """
+    reports = [simulate(CINDER, 50, seed) for seed in (1, 2, 3)]
+    kills = [r for r in reports if r.wyrm_killed]
+    assert kills, "the greedy bot never slew the Magma Wyrm across the seed sweep"
+    for r in kills:
+        assert r.day_of_first_wyrm_kill is not None
+        assert 1 <= r.day_of_first_wyrm_kill <= 50
+
+
+# ---------------------------------------------------------------------------
+# robustness on non-shipped pack shapes: location doors inside hunt zones
+#
+# The bot runs arbitrary authored packs, not just the two bundled worlds, so a
+# zone may overlap a location door. A door cell is "walkable" (you can step onto
+# it) but standing on it flips the bot into that location's MENU — useless ground
+# for a forest fight, and a "fight" issued from a MENU is rejected by the engine
+# WITHOUT spending a turn. These pin the two guards that keep that from spinning
+# the per-day loop or over-counting fights.
+# ---------------------------------------------------------------------------
+
+
+def _door(x: int, y: int) -> LocationDef:
+    """A bare location door placed at ``(x, y)`` (an inn, for concreteness)."""
+    return LocationDef(
+        key="inn",
+        kind="inn",
+        name="Wayhouse",
+        x=x,
+        y=y,
+        glyph="⌂",
+        color="town",
+        actions=("rest", "leave"),
+    )
+
+
+def test_nearest_in_zone_skips_a_door_cell() -> None:
+    """A door is never returned as a zone's hunt cell, even when it is nearest.
+
+    The zone here spans a column running away from the spawn; its closest-to-spawn
+    walkable cell IS a location door, with open ground one step further. The
+    helper must skip the door (it would only trap the bot in a menu) and return
+    the open cell beyond it — the FIX-2 filter, mirroring ``_adjacent_open``.
+    """
+    # 11x11 grass; spawn (5, 5). A door at (5, 6) is the nearest cell inside the
+    # zone (Manhattan 1); the nearest OPEN in-zone cell is (5, 7) (Manhattan 2).
+    world = make_world(
+        locations=[_door(5, 6)],
+        zones=[Zone(key="wood", x0=5, y0=6, x1=5, y1=9, tier_lo=1, tier_hi=1)],
+    )
+    walkable = sim._reachable(world)
+    assert (5, 6) in walkable  # the door cell is walkable...
+    cell = sim._nearest_in_zone(world, walkable, world.zones[0])
+    assert cell is not None
+    assert cell != (5, 6)  # ...but the helper does not pick it
+    assert world.location_at(*cell) is None  # the returned cell is open ground
+    assert cell == (5, 7)  # the nearest open in-zone cell beyond the door
+
+
+def test_zone_hunt_spots_drops_a_zone_with_no_fightable_foe() -> None:
+    """A zone whose tier band holds no foe is dropped, not appended with None.
+
+    FIX-4: the fallback in ``_best_hunt_spot`` (``ranked[-1]``) must never land on
+    a zone where no monster can roll. A zone banded to a tier with no monster is
+    simply not a hunting ground, so it never enters the spot list.
+    """
+    # One zone banded to tier 9 (no monster lives there); the only monster is a
+    # tier-1 rat. The empty-band zone must be dropped entirely.
+    world = make_world(
+        monsters=[make_monster(tier=1)],
+        zones=[Zone(key="void", x0=4, y0=4, x1=6, y1=6, tier_lo=9, tier_hi=9)],
+    )
+    spots = sim._zone_hunt_spots(world, sim._reachable(world))
+    assert spots == []  # the foe-less zone is not a spot
+
+
+def test_hunt_yields_the_turn_when_stuck_in_a_menu(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    """A hunt that ends in a MENU yields the turn instead of over-counting.
+
+    The defence-in-depth for FIX-1: should the bot ever reach the fight moment
+    still inside a location MENU (a door swallowed the walk), the engine would
+    REJECT the "fight" without spending a turn — and the old string-only check
+    misread that reject as a won bout, over-counting and spinning the loop. The
+    new mode pre-check must instead leave the menu and return False (yield), so no
+    phantom fight is recorded and the day loop makes honest progress.
+    """
+    # A door at (5, 4) inside a tier-1 zone. We inject this door cell as the hunt
+    # spot directly — the pre-FIX-2 state where a door WAS the nearest in-zone
+    # cell — so the guard, not the spot-selection filter, is what is under test.
+    world = make_world(
+        locations=[_door(5, 4)],
+        zones=[Zone(key="wood", x0=4, y0=3, x1=6, y1=5, tier_lo=1, tier_hi=1)],
+        monsters=[make_monster(tier=1)],
+    )
+    clock = sim._Clock(sim._SIM_START)
+    game = Game(world, Store(tmp_path / "g.db"), clock=clock, rng=GameRNG(seed=1))  # type: ignore[arg-type]
+    bot = sim._Bot(game, world, clock)
+    game.join(bot.name)
+    bot._hunt_spots = [(1, (5, 4), make_monster(tier=1))]
+    player = game.players[bot.name]
+
+    # Model "a location door swallowed the walk": every navigation step ends with
+    # the bot back inside the door's menu, so the hunt reaches its fight decision
+    # still in MENU mode no matter how many times it tries to step clear — exactly
+    # the trap the guard exists for (a single un-menu + re-walk cannot escape it).
+    def _walk_into_door(_goal: tuple[int, int]) -> None:
+        player.mode = Mode.MENU
+        player.at_location = "inn"
+
+    monkeypatch.setattr(bot, "_goto_xy", _walk_into_door)
+    _walk_into_door((5, 4))  # start the hunt already inside the menu
+
+    fought = bot._hunt()
+
+    assert fought is False  # the turn is yielded, not spent on a menu-reject
+    assert bot.fights_fought == 0  # no phantom fight recorded
+    assert game.players[bot.name].mode is Mode.TILE  # and the menu was left behind

examples/door-game/tests/test_social.py

@@ -0,0 +1,862 @@
+"""The v0.5 social slice — ambush (async PvP), inn mail, and inn dice.
+
+Drives the game façade over the shipped world with a frozen clock and a seeded
+RNG. Three feature areas:
+
+* AMBUSH — the full eligibility matrix (every refusal branch), the win path
+  (exact gold transfer, victim bounced to spawn at 1 HP, private mail visible
+  only to the victim, public news), the lose path (attacker bounced, no
+  transfer), the flee stalemate, per-day once-per-pair, and next-day retry.
+* MAIL — ``post`` delivers a private note to the target's log once, the sender
+  is confirmed, the daily cap refuses the overflow, the sanitizer rejects a
+  newline body, and the Watch state payload NEVER carries a targeted row.
+* DICE — win/lose/push under a seeded RNG, the bet band, affordability, the
+  daily cap (a push still counts), and the Herald firing only on a big win.
+
+Negative-test discipline (the SLEEP RULE has teeth):
+  ``test_sleep_rule_guard_has_teeth`` documents the revert-and-observe check.
+  Disabling the ``target.turn_day >= today`` clause in Game._ambush_refusal
+  let an ALREADY-AWAKE target be ambushed — ``test_ambush_refused_target_awake``
+  then failed (the attempt resolved instead of being refused). The clause was
+  restored; that refusal test is the standing regression for the invariant.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from tests.conftest import fixed_clock, utc
+from understone.engine.models import Mode
+from understone.engine.rng import GameRNG
+from understone.game import Game
+from understone.persistence import Store
+from understone.watch import build_state_payload
+from understone.world.loader import load_world
+
+PACK = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+# The frozen "today" all these tests run on; the sleep rule keys off its ordinal.
+_NOW = utc(2026, 6, 12, 10, 0)
+_TODAY = _NOW.toordinal()
+
+
+@pytest.fixture
+def clock() -> object:
+    return fixed_clock(_NOW)
+
+
+def _game(tmp_path: Path, clock: object, seed: int = 7) -> Game:
+    world = load_world(PACK)
+    store = Store(tmp_path / "social.db")
+    return Game(world, store, clock=clock, rng=GameRNG(seed=seed))  # type: ignore[arg-type]
+
+
+def _arm_ambush(
+    game: Game,
+    *,
+    attacker_level: int = 5,
+    target_level: int = 5,
+    target_asleep: bool = True,
+    target_gold: int = 100,
+) -> tuple[object, object]:
+    """Join an attacker + target and tune their sheets for an ambush.
+
+    The attacker is overworld and seasoned; the target sits at *target_level*
+    with *target_gold*, and ``target_asleep`` controls the sleep rule (a
+    sleeping target has not acted today). Returns ``(attacker, target)``.
+    """
+    game.join("Raider")
+    game.join("Sleeper")
+    attacker = game.players["Raider"]
+    target = game.players["Sleeper"]
+    attacker.level = attacker_level
+    target.level = target_level
+    target.gold = target_gold
+    target.turn_day = _TODAY - 1 if target_asleep else _TODAY
+    return attacker, target
+
+
+# ---------------------------------------------------------------------------
+# Ambush — eligibility matrix (each refusal is a distinct in-fiction line)
+# ---------------------------------------------------------------------------
+
+
+def test_ambush_refused_unknown_target(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Raider")
+    game.players["Raider"].level = 5
+    out = game.action("Raider", "ambush", "Ghost", "")
+    assert "signed the ledger" in out  # the unknown-player refusal
+    # No turn spent on an unresolvable target.
+    assert game.players["Raider"].turns_left == game.world.settings.daily_turns
+
+
+def test_ambush_refused_self(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Raider")
+    game.players["Raider"].level = 5
+    out = game.action("Raider", "ambush", "Raider", "")
+    assert "yourself" in out.lower()
+
+
+def test_ambush_refused_young_attacker(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    floor = game.world.settings.ambush_min_level
+    _arm_ambush(game, attacker_level=floor - 1, target_level=floor + 1)
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "shields the young" in out
+    assert game.players["Raider"].turns_left == game.world.settings.daily_turns
+
+
+def test_ambush_refused_young_target(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    floor = game.world.settings.ambush_min_level
+    # Attacker is seasoned but the target is below the floor: still shielded.
+    _arm_ambush(game, attacker_level=floor + 1, target_level=floor - 1)
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "shields the young" in out
+
+
+def test_ambush_refused_out_of_band(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    band = game.world.settings.ambush_level_band
+    floor = game.world.settings.ambush_min_level
+    _arm_ambush(
+        game,
+        attacker_level=floor + band + 5,
+        target_level=floor,
+    )
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "far from your measure" in out
+
+
+def test_ambush_band_beats_awake_in_refusal_order(tmp_path: Path, clock: object) -> None:
+    """PRECEDENCE: the band gate is checked before the sleep rule.
+
+    A target who is BOTH out of band AND awake must report the band message,
+    not the watchful one — pinning the documented order (level gates before the
+    live-play sleep defence).
+    """
+    game = _game(tmp_path, clock)
+    band = game.world.settings.ambush_level_band
+    floor = game.world.settings.ambush_min_level
+    _arm_ambush(
+        game,
+        attacker_level=floor + band + 1,  # one past the band...
+        target_level=floor,
+        target_asleep=False,  # ...and also awake
+    )
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "far from your measure" in out  # the band gate wins
+    assert "watchful today" not in out
+
+
+def test_ambush_band_boundary_exact_is_allowed(tmp_path: Path, clock: object) -> None:
+    """Exactly ``ambush_level_band`` apart clears the band gate (it is inclusive).
+
+    Armed awake so the very next gate — the sleep rule — is what speaks: a
+    'watchful today' refusal proves the band gate let this pair through.
+    """
+    game = _game(tmp_path, clock)
+    band = game.world.settings.ambush_level_band
+    floor = game.world.settings.ambush_min_level
+    _arm_ambush(
+        game,
+        attacker_level=floor + band,  # exactly band levels above the floor
+        target_level=floor,
+        target_asleep=False,
+    )
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "far from your measure" not in out  # past the band gate
+    assert "watchful today" in out  # stopped by the next gate instead
+
+
+def test_ambush_band_boundary_one_over_is_refused(tmp_path: Path, clock: object) -> None:
+    """One level past ``ambush_level_band`` is refused with the band message."""
+    game = _game(tmp_path, clock)
+    band = game.world.settings.ambush_level_band
+    floor = game.world.settings.ambush_min_level
+    _arm_ambush(
+        game,
+        attacker_level=floor + band + 1,  # just over the band
+        target_level=floor,
+    )
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "far from your measure" in out
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is False
+
+
+def test_ambush_refused_target_awake(tmp_path: Path, clock: object) -> None:
+    """The SLEEP RULE: a target who has already acted today is un-ambushable.
+
+    See the module docstring for the revert-and-observe check proving this
+    refusal has teeth.
+    """
+    game = _game(tmp_path, clock)
+    _arm_ambush(game, target_asleep=False)
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "watchful today" in out
+    # Refused without resolving: no turn spent, no ambush recorded.
+    assert game.players["Raider"].turns_left == game.world.settings.daily_turns
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is False
+
+
+def test_ambush_refused_repeat_same_pair_same_day(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game)
+    # First attempt resolves (attacker overwhelming -> a clean win).
+    attacker.atk = 200
+    target.hp = 5
+    game.action("Raider", "ambush", "Sleeper", "")
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is True
+    # Re-arm the target as sleeping AND healed above 1 HP (so the mercy rule
+    # does not intercept first); the SAME pair is still barred for the day.
+    target.turn_day = _TODAY - 1
+    target.hp = 20
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "already lain in wait" in out
+
+
+def test_ambush_refused_pile_on_downed_victim(tmp_path: Path, clock: object) -> None:
+    """MERCY RULE: a second, DIFFERENT attacker cannot kick a just-bounced sleeper.
+
+    The first ambush leaves the victim at 1 HP (still asleep — being robbed does
+    not start their day). A fresh raider then finds them battered in the ditch;
+    even bandits have standards, so the pile-on is refused outright — no turn
+    spent, no pair-row written for the second attacker.
+    """
+    game = _game(tmp_path, clock)
+    first, target = _arm_ambush(game, target_gold=100)
+    first.atk = 200  # one-shot: leaves the victim at 1 HP
+    target.hp = 5
+    game.action("Raider", "ambush", "Sleeper", "")
+    assert target.hp == 1  # downed and still asleep
+
+    # A second, seasoned raider tries to finish the job.
+    game.join("Marauder")
+    second = game.players["Marauder"]
+    second.level = 5
+    turns_before = second.turns_left
+    out = game.action("Marauder", "ambush", "Sleeper", "")
+
+    assert "battered in the ditch" in out
+    # No turn spent and no attempt recorded for the second attacker.
+    assert second.turns_left == turns_before
+    assert game.store.has_ambushed("Marauder", "Sleeper", _TODAY) is False
+
+
+def test_ambush_healed_victim_is_ambushable_again(tmp_path: Path, clock: object) -> None:
+    """The mercy rule lifts once the victim mends: healed above 1 HP (and still
+    asleep), a fresh attacker may strike."""
+    game = _game(tmp_path, clock)
+    first, target = _arm_ambush(game, target_gold=100)
+    first.atk = 200
+    target.hp = 5
+    game.action("Raider", "ambush", "Sleeper", "")
+    assert target.hp == 1
+
+    # The victim is tended back above the floor (still asleep this day).
+    target.hp = 18
+    game.join("Marauder")
+    second = game.players["Marauder"]
+    second.level = 5
+    second.atk = 200  # one-shot again
+    out = game.action("Marauder", "ambush", "Sleeper", "")
+
+    assert "battered in the ditch" not in out
+    # The fresh ambush resolved: recorded, and the victim is bounced anew.
+    assert game.store.has_ambushed("Marauder", "Sleeper", _TODAY) is True
+    assert target.hp == 1
+
+
+def test_ambush_refused_zero_turns(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    attacker, _ = _arm_ambush(game)
+    attacker.turns_left = 0
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "spent for today" in out.lower()
+    # Eligible but exhausted: nothing recorded (the attempt never landed).
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is False
+
+
+# ---------------------------------------------------------------------------
+# Ambush — outcomes (win / lose / flee) and the records they leave
+# ---------------------------------------------------------------------------
+
+
+def test_ambush_win_transfers_gold_and_bounces_victim(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=100)
+    attacker.atk = 200  # one-shot the sleeper
+    target.hp = 5
+    pct = game.world.settings.ambush_gold_pct
+    steal = 100 * pct // 100  # 25 gold at the shipped 25%
+    raider_gold_before = attacker.gold
+
+    out = game.action("Raider", "ambush", "Sleeper", "")
+
+    # Exact transfer: attacker up by steal, victim down by the same.
+    assert attacker.gold == raider_gold_before + steal
+    assert target.gold == 100 - steal
+    # The victim wakes at the spawn at 1 HP, knocked out of any menu.
+    assert target.hp == 1
+    assert (target.x, target.y) == game.world.spawn
+    assert target.mode is Mode.TILE
+    assert target.at_location == ""
+    assert f"{steal} gold" in out
+    # The attempt is recorded.
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is True
+
+
+def test_ambush_steals_only_carried_gold_not_the_vault(tmp_path: Path, clock: object) -> None:
+    """A winning ambush robs carried gold only — banked vault gold is untouched.
+
+    The steal is a slice of ``target.gold`` (gold in hand); the strongbox
+    (``banked``) is safe by design. This pins the vault's whole point: bank your
+    coin before you sleep and a sleeping-robber cannot lift it.
+    """
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=40)
+    target.banked = 1000  # a fat vault the raider must not be able to touch
+    attacker.atk = 200  # one-shot the sleeper
+    target.hp = 5
+    pct = game.world.settings.ambush_gold_pct
+    steal = 40 * pct // 100  # a slice of the CARRIED 40, not the banked 1000
+
+    game.action("Raider", "ambush", "Sleeper", "")
+
+    assert target.gold == 40 - steal  # carried gold robbed
+    assert target.banked == 1000  # the vault is wholly untouched
+    assert attacker.gold == game.world.settings.starting_gold + steal
+
+
+def test_ambush_win_applies_attacker_wear(tmp_path: Path, clock: object) -> None:
+    """A multi-round win banks the attacker's wear: the log narrates the
+    sleeper's counter-blows, so the sheet must show the HP they cost.
+
+    The one-shot win above leaves the attacker untouched, which would mask a
+    WIN branch that drops ``hp_delta`` on the floor. Here the sleeper is tanky
+    enough to trade blows before falling (and the attacker still wins), so the
+    attacker must end below full HP. Stats and seed are tuned so the win is
+    decisive but not instant.
+    """
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=100)
+    attacker.atk, attacker.def_ = 8, 2
+    attacker.hp = attacker.max_hp = 30
+    target.atk, target.def_, target.hp = 5, 1, 25
+
+    out = game.action("Raider", "ambush", "Sleeper", "")
+
+    # The win lands (victim robbed and bounced to 1 HP)...
+    assert target.hp == 1
+    assert (
+        any(crow in out for crow in ("made off", "robbed the sleeping", "lifted")) or "rob" in out
+    )
+    # ...but the sleeper's counter-blows cost the attacker real HP this time.
+    assert attacker.hp < attacker.max_hp
+    assert attacker.hp >= 1  # never below the floor
+
+
+def test_ambush_win_news_is_public_and_mail_is_private(tmp_path: Path, clock: object) -> None:
+    """The victory crows on the public feed; the victim gets a PRIVATE note.
+
+    A THIRD player must see the public ambush line but never the private one.
+    """
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=80)
+    attacker.atk = 200
+    target.hp = 5
+    game.join("Bystander")  # a third player who must never see the private note
+
+    game.action("Raider", "ambush", "Sleeper", "")
+
+    # The victim reads the private "While you slept" note in their own log.
+    victim_log = game.log("Sleeper")
+    assert "While you slept" in victim_log
+    assert "ambushed you" in victim_log
+
+    # The bystander sees the public crow but NOT the private note.
+    third_log = game.log("Bystander")
+    assert (
+        "made off with" in third_log
+        or "robbed the sleeping" in third_log
+        or ("lifted" in third_log)
+    )
+    assert "While you slept" not in third_log
+
+
+def test_ambush_win_on_pauper_steals_nothing_but_still_lands(tmp_path: Path, clock: object) -> None:
+    """A win over a penniless sleeper: steal is 0, but the beat still plays.
+
+    The victim is bounced to the spawn at 1 HP all the same, the public herald
+    crows the robbery, and the private 'while you slept' note still reaches the
+    victim — the gold transfer being empty changes none of that.
+    """
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=0)
+    attacker.atk = 200  # one-shot the sleeper
+    target.hp = 5
+    game.join("Bystander")
+    raider_gold_before = attacker.gold
+
+    out = game.action("Raider", "ambush", "Sleeper", "")
+
+    # Nothing to steal: both purses are unchanged by the transfer.
+    assert attacker.gold == raider_gold_before
+    assert target.gold == 0
+    assert "0 gold" in out
+    # The victim is still bounced to the spawn at 1 HP.
+    assert target.hp == 1
+    assert (target.x, target.y) == game.world.spawn
+    assert target.mode is Mode.TILE
+    assert target.at_location == ""
+
+    # Public herald fires (a bystander reads the crow)...
+    third_log = game.log("Bystander")
+    assert any(crow in third_log for crow in ("made off", "robbed the sleeping", "lifted"))
+    # ...and the private mail still reaches the victim.
+    victim_log = game.log("Sleeper")
+    assert "While you slept" in victim_log
+    assert "ambushed you" in victim_log
+
+
+def test_ambush_lose_bounces_attacker_no_transfer(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=100)
+    # The sleeper is deadly: the ambush rebounds onto the attacker.
+    target.atk = 200
+    target.def_ = 100
+    target.hp = 200
+    attacker_gold_before = attacker.gold
+
+    out = game.action("Raider", "ambush", "Sleeper", "")
+
+    # No gold moved; the ATTACKER is the one bounced to spawn at 1 HP.
+    assert attacker.gold == attacker_gold_before
+    assert target.gold == 100
+    assert attacker.hp == 1
+    assert (attacker.x, attacker.y) == game.world.spawn
+    assert "flee" in out.lower() or "wakes" in out.lower()
+    # The attempt is still spent.
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is True
+
+
+def test_ambush_records_attempt_on_every_outcome(tmp_path: Path, clock: object) -> None:
+    """Win, lose, or flee — the (attacker, target, day) row is always written."""
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game)
+    # Tune a flee: when neither side can meaningfully dent the other, the fight
+    # grinds to the 50-round stalemate guard, which resolves as FLED with no
+    # transfer. Both deal the 1-damage floor (atk << def), and both carry far
+    # more HP than 50 rounds can drain, so neither drops first.
+    attacker.atk, attacker.def_ = 1, 200
+    attacker.hp = attacker.max_hp = 500
+    target.atk, target.def_, target.hp = 1, 200, 500
+    gold_before = attacker.gold
+
+    out = game.action("Raider", "ambush", "Sleeper", "")
+
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is True
+    assert attacker.gold == gold_before  # a flee moves no gold
+    assert "slip away" in out.lower() or "nerve" in out.lower()
+
+
+def test_ambush_next_day_retry_allowed(tmp_path: Path, clock: object) -> None:
+    """A new UTC day clears the once-per-pair lock (advance the injected clock)."""
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game)
+    attacker.atk = 200
+    target.hp = 5
+    game.action("Raider", "ambush", "Sleeper", "")
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is True
+
+    # Advance past UTC midnight; re-arm the sleeper for the new day.
+    tomorrow = utc(2026, 6, 13, 9, 0)
+    game.clock = fixed_clock(tomorrow)  # type: ignore[assignment]
+    target.turn_day = tomorrow.toordinal() - 1  # asleep again
+    target.hp = 5
+    out = game.action("Raider", "ambush", "Sleeper", "")
+    assert "already lain in wait" not in out  # the new day permits a fresh attempt
+    assert game.store.has_ambushed("Raider", "Sleeper", tomorrow.toordinal()) is True
+
+
+def test_sleep_rule_guard_has_teeth(tmp_path: Path, clock: object) -> None:
+    """Pin the sleep rule on a single-field divergence.
+
+    The un-ambushable case and the ambushable case differ ONLY in ``turn_day``:
+    with the target awake the action is refused, and flipping that one field to
+    asleep makes the very same attempt resolve and record.
+    """
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_asleep=False)
+    attacker.atk = 200
+    target.hp = 5
+    refused = game.action("Raider", "ambush", "Sleeper", "")
+    assert "watchful today" in refused
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is False
+
+    # Flip ONLY the sleep field; now the very same attempt lands.
+    target.turn_day = _TODAY - 1
+    resolved = game.action("Raider", "ambush", "Sleeper", "")
+    assert "watchful today" not in resolved
+    assert game.store.has_ambushed("Raider", "Sleeper", _TODAY) is True
+
+
+def test_ambush_both_rows_persist_in_one_transaction(tmp_path: Path, clock: object) -> None:
+    """A win commits BOTH fighters' rows; a store reopen sees the transfer."""
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=100)
+    attacker.atk = 200
+    target.hp = 5
+    game.action("Raider", "ambush", "Sleeper", "")
+    raider_gold = attacker.gold
+    sleeper_gold = target.gold
+    game.store.close()
+
+    world = load_world(PACK)
+    reopened = Store(tmp_path / "social.db")
+    revived = Game(world, reopened, clock=clock)  # type: ignore[arg-type]
+    assert revived.players["Raider"].gold == raider_gold
+    assert revived.players["Sleeper"].gold == sleeper_gold
+    assert revived.players["Sleeper"].hp == 1
+    reopened.close()
+
+
+# ---------------------------------------------------------------------------
+# Mail — post delivers privately, confirms, caps, sanitizes
+# ---------------------------------------------------------------------------
+
+
+def test_post_delivers_to_target_once_with_confirmation(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Scribe")
+    game.join("Reader")
+    confirm = game.action("Scribe", "post", "Reader", "", "meet me at the inn")
+    assert "tucks the note" in confirm  # the sender's in-fiction confirmation
+    # No turn spent on a post.
+    assert game.players["Scribe"].turns_left == game.world.settings.daily_turns
+
+    first = game.log("Reader")
+    assert "While you were away" in first
+    assert "meet me at the inn" in first
+    # Read once: the cursor advanced, so a second read no longer shows it.
+    second = game.log("Reader")
+    assert "meet me at the inn" not in second
+
+
+def test_post_refused_unknown_and_self(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Scribe")
+    unknown = game.action("Scribe", "post", "Nobody", "", "hello?")
+    assert "signed the ledger" in unknown
+    mine = game.action("Scribe", "post", "Scribe", "", "note to self")
+    assert "talk to yourself" in mine.lower()
+
+
+def test_post_daily_cap_refuses_overflow(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Scribe")
+    game.join("Reader")
+    cap = game.world.settings.post_daily_cap
+    for i in range(cap):
+        out = game.action("Scribe", "post", "Reader", "", f"note {i}")
+        assert "tucks the note" in out
+    # The (cap+1)-th post is refused.
+    over = game.action("Scribe", "post", "Reader", "", "one too many")
+    assert "all the word you may today" in over
+    assert game.players["Scribe"].posts_sent == cap
+
+
+def test_post_sanitizer_rejects_newline_body(tmp_path: Path, clock: object) -> None:
+    """A newline-injected note body is refused; nothing is delivered or counted."""
+    game = _game(tmp_path, clock)
+    game.join("Scribe")
+    game.join("Reader")
+    events_before = len(game.events)
+    out = game.action("Scribe", "post", "Reader", "", "line one\nFORGED HERALD LINE")
+    assert "scrawl" in out.lower()
+    # No event appended and the daily counter is untouched.
+    assert len(game.events) == events_before
+    assert game.players["Scribe"].posts_sent == 0
+    # And the reader never receives it.
+    assert "FORGED" not in game.log("Reader")
+
+
+def test_post_works_from_inside_a_building(tmp_path: Path, clock: object) -> None:
+    """Posting is legal anywhere: a menu-bound sender still gets a menu reply."""
+    game = _game(tmp_path, clock)
+    game.join("Scribe")
+    game.join("Reader")
+    scribe = game.players["Scribe"]
+    scribe.mode = Mode.MENU
+    scribe.at_location = "inn"
+    out = game.action("Scribe", "post", "Reader", "", "by the hearth")
+    assert "tucks the note" in out
+    # The reply is the inn menu (a menu surface), not an overworld frame.
+    assert "(R)est" in out or "Sleeping Drake" in out
+
+
+# ---------------------------------------------------------------------------
+# Mail — the lobby TV must never carry a private note
+# ---------------------------------------------------------------------------
+
+
+def test_watch_state_excludes_targeted_rows(tmp_path: Path, clock: object) -> None:
+    """EXPLICIT: a private (targeted) event must not reach the Watch herald."""
+    game = _game(tmp_path, clock)
+    game.join("Scribe")
+    game.join("Reader")
+    game.action("Scribe", "post", "Reader", "", "a secret for the Reader")
+
+    payload = build_state_payload(game)
+    herald = payload["herald"]
+    assert isinstance(herald, list)
+    texts = [row["text"] for row in herald]
+    # The join lines are public and present; the private note is absent.
+    assert any("Scribe" in t or "Reader" in t for t in texts)  # public joins show
+    assert all("a secret for the Reader" not in t for t in texts)
+
+
+def test_watch_state_excludes_private_ambush_note(tmp_path: Path, clock: object) -> None:
+    """The ambush victim's private alert is filtered from the lobby TV too."""
+    game = _game(tmp_path, clock)
+    attacker, target = _arm_ambush(game, target_gold=80)
+    attacker.atk = 200
+    target.hp = 5
+    game.action("Raider", "ambush", "Sleeper", "")
+
+    herald_texts = [row["text"] for row in build_state_payload(game)["herald"]]  # type: ignore[union-attr]
+    # The PUBLIC ambush crow is on the feed...
+    assert any(
+        "Sleeper" in t and ("made off" in t or "robbed" in t or "lifted" in t) for t in herald_texts
+    )
+    # ...but the PRIVATE "While you slept" note never is.
+    assert all("While you slept" not in t for t in herald_texts)
+
+
+# ---------------------------------------------------------------------------
+# Dice — win / lose / push under a seeded RNG, bands, cap, herald gate
+# ---------------------------------------------------------------------------
+
+
+def _at_inn(game: Game, name: str) -> object:
+    """Join *name* and seat them at the inn (MENU surface)."""
+    game.join(name)
+    player = game.players[name]
+    player.mode = Mode.MENU
+    player.at_location = "inn"
+    return player
+
+
+def test_gamble_win_under_seeded_rng(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 100
+    # Seed 2 makes the gamble child roll 11 (you) vs 9 (house) -> a win.
+    game.rng = GameRNG(seed=2)
+    out = game.action("Gambler", "gamble", "", "", "", 10)
+    assert player.gold == 110  # stake doubled back
+    assert "win" in out.lower()
+    # No turn spent; one game counted.
+    assert player.turns_left == game.world.settings.daily_turns
+    assert player.gambles == 1
+
+
+def test_gamble_lose_under_seeded_rng(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 100
+    # Seed 0 rolls 4 (you) vs 9 (house) -> a loss.
+    game.rng = GameRNG(seed=0)
+    out = game.action("Gambler", "gamble", "", "", "", 10)
+    assert player.gold == 90
+    assert "lose" in out.lower()
+    assert player.gambles == 1
+
+
+def test_gamble_push_under_seeded_rng(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 100
+    # Seed 1 rolls 6 vs 6 -> a push: no gold change, but it still counts.
+    game.rng = GameRNG(seed=1)
+    out = game.action("Gambler", "gamble", "", "", "", 10)
+    assert player.gold == 100
+    assert "push" in out.lower()
+    assert player.gambles == 1  # a push still consumes a daily game
+
+
+def test_gamble_bet_band_refused(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 100_000
+    max_bet = game.world.settings.gamble_max_bet
+    low = game.action("Gambler", "gamble", "", "", "", 0)
+    assert f"1 to {max_bet}" in low
+    high = game.action("Gambler", "gamble", "", "", "", max_bet + 1)
+    assert f"1 to {max_bet}" in high
+    # A rejected bet neither moves gold nor counts toward the cap.
+    assert player.gold == 100_000
+    assert player.gambles == 0
+
+
+def test_gamble_unaffordable_refused(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 5
+    out = game.action("Gambler", "gamble", "", "", "", 10)  # within band, can't cover
+    assert "can't cover" in out.lower()
+    assert player.gold == 5
+    assert player.gambles == 0
+
+
+def test_gamble_daily_cap_refused(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 100_000
+    cap = game.world.settings.gamble_daily_cap
+    player.gambles = cap  # already at the cap
+    out = game.action("Gambler", "gamble", "", "", "", 5)
+    assert "enough for one day" in out
+    assert player.gambles == cap  # not incremented past the cap
+
+
+def test_gamble_outside_inn_refused(tmp_path: Path, clock: object) -> None:
+    """The dice live at the inn: the verb is illegal in another building."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.at_location = "shop"  # the shop has no 'gamble' action
+    player.gold = 100
+    out = game.action("Gambler", "gamble", "", "", "", 10)
+    assert "can't 'gamble' here" in out.lower()
+    assert player.gold == 100
+
+
+def test_gamble_big_win_heralds(tmp_path: Path, clock: object) -> None:
+    """A win of >= 25 gold reaches the public Herald; a small one does not."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 1000
+
+    # A 50-gold win (>= the 25 threshold) writes a public dice line.
+    game.rng = GameRNG(seed=2)  # a winning roll
+    events_before = len(game.events)
+    game.action("Gambler", "gamble", "", "", "", 50)
+    new = game.events[events_before:]
+    assert any(e.kind == "gamble" and e.target == "" for e in new)
+    assert player.gold == 1050
+
+
+def test_gamble_small_win_is_quiet(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Gambler")
+    player.gold = 1000
+    # A 10-gold win is below the 25-gold Herald threshold: no public line.
+    game.rng = GameRNG(seed=2)
+    events_before = len(game.events)
+    game.action("Gambler", "gamble", "", "", "", 10)
+    new = game.events[events_before:]
+    assert all(e.kind != "gamble" for e in new)
+    assert player.gold == 1010
+
+
+# ---------------------------------------------------------------------------
+# The Vault — deposit/withdraw at the inn (no turn; banked gold is safe)
+# ---------------------------------------------------------------------------
+
+
+def test_deposit_moves_gold_to_the_vault_no_turn(tmp_path: Path, clock: object) -> None:
+    """Deposit moves coin from hand to vault, costs no turn, and is friendly."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Saver")
+    player.gold = 100
+    turns_before = player.turns_left
+
+    out = game.action("Saver", "deposit", "", "", "", 60)
+
+    assert player.gold == 40
+    assert player.banked == 60
+    assert player.turns_left == turns_before  # banking spends no turn
+    assert "strongbox" in out.lower()
+
+
+def test_withdraw_moves_gold_back_to_hand(tmp_path: Path, clock: object) -> None:
+    """Withdraw moves coin from vault to hand."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Saver")
+    player.gold = 10
+    player.banked = 90
+
+    game.action("Saver", "withdraw", "", "", "", 50)
+
+    assert player.gold == 60
+    assert player.banked == 40
+
+
+def test_deposit_amount_exceeding_holdings_refused(tmp_path: Path, clock: object) -> None:
+    """Depositing more than you carry is refused without mutation."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Saver")
+    player.gold = 30
+    player.banked = 0
+
+    out = game.action("Saver", "deposit", "", "", "", 50)
+
+    assert player.gold == 30  # unchanged
+    assert player.banked == 0
+    assert "1 to 30" in out
+
+
+def test_deposit_with_nothing_in_hand_refused(tmp_path: Path, clock: object) -> None:
+    """Depositing with an empty hand is a friendly refusal."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Saver")
+    player.gold = 0
+
+    out = game.action("Saver", "deposit", "", "", "", 10)
+
+    assert player.banked == 0
+    assert "no coin" in out.lower()
+
+
+def test_withdraw_amount_exceeding_vault_refused(tmp_path: Path, clock: object) -> None:
+    """Withdrawing more than is banked is refused without mutation."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Saver")
+    player.gold = 0
+    player.banked = 20
+
+    out = game.action("Saver", "withdraw", "", "", "", 50)
+
+    assert player.gold == 0
+    assert player.banked == 20  # unchanged
+    assert "1 to 20" in out
+
+
+def test_withdraw_empty_vault_refused(tmp_path: Path, clock: object) -> None:
+    """Withdrawing from an empty vault is a friendly refusal."""
+    game = _game(tmp_path, clock)
+    player = _at_inn(game, "Saver")
+    player.banked = 0
+
+    out = game.action("Saver", "withdraw", "", "", "", 10)
+
+    assert player.gold == game.world.settings.starting_gold  # unchanged
+    assert "empty" in out.lower()
+
+
+def test_status_shows_carried_and_vault_gold(tmp_path: Path, clock: object) -> None:
+    """door_status reports gold as carried-on-hand plus banked-in-the-vault."""
+    game = _game(tmp_path, clock)
+    game.join("Saver")
+    player = game.players["Saver"]
+    player.gold = 75
+    player.banked = 250
+
+    out = game.status("Saver")
+
+    assert "75 on hand" in out
+    assert "250 in the vault" in out

examples/door-game/tests/test_texture.py

@@ -0,0 +1,60 @@
+"""Deterministic terrain texturing (understone.screen.texture).
+
+Pins the contract the Watch JS mirrors: a textured glyph is a pure function of
+its cell coordinate (stable per cell), an un-listed glyph is returned
+untouched, and the selection formula is ``(x * _HASH_X + y * _HASH_Y) % n``
+derived from the module's hash constants. The formula is asserted against those
+constants so a retune moves the test with it and a drift is caught.
+"""
+
+from __future__ import annotations
+
+from understone.screen.texture import _HASH_X, _HASH_Y, VARIANTS, textured
+
+
+def test_untextured_glyph_is_unchanged() -> None:
+    """A glyph with no VARIANTS row passes through verbatim (actors, walls)."""
+    for ch in "█@☻⌂$":
+        assert textured(ch, 3, 7) == ch
+
+
+def test_same_coord_same_variant() -> None:
+    """Texturing is position-only and stable: one cell always picks one glyph."""
+    first = textured(".", 12, 5)
+    for _ in range(5):
+        assert textured(".", 12, 5) == first
+
+
+def test_variant_is_always_in_the_row() -> None:
+    """Every selected glyph is one of the declared variants for its base."""
+    choices = VARIANTS["."]
+    for x in range(20):
+        for y in range(20):
+            assert textured(".", x, y) in choices
+
+
+def test_a_row_uses_more_than_one_variant() -> None:
+    """Across a row the hash spreads — the texture is not a single repeated glyph."""
+    seen = {textured(".", x, 0) for x in range(len(VARIANTS["."]) * 4)}
+    assert len(seen) > 1
+
+
+def test_formula_matches_the_hash_constants() -> None:
+    """The selection index is (x * _HASH_X + y * _HASH_Y) % len — the JS twin's formula.
+
+    Derived from the live ``_HASH_X`` / ``_HASH_Y`` constants (not the literal
+    31/17) and checked against the live VARIANTS rows, so it stays a formula
+    test that tracks a retune rather than a snapshot a table or constant edit
+    could silently invalidate.
+    """
+    for base, choices in VARIANTS.items():
+        n = len(choices)
+        for x, y in [(0, 0), (1, 0), (0, 1), (12, 5), (7, 13), (255, 255)]:
+            assert textured(base, x, y) == choices[(x * _HASH_X + y * _HASH_Y) % n]
+
+
+def test_origin_cell_is_the_base_glyph() -> None:
+    """Cell (0,0) hashes to index 0, which is the base glyph (variants[0])."""
+    for base, choices in VARIANTS.items():
+        assert textured(base, 0, 0) == choices[0]
+        assert choices[0] == base

examples/door-game/tests/test_textwidth.py

@@ -0,0 +1,81 @@
+"""The one-glyph-one-column grid contract (understone.engine.textwidth).
+
+Pins the accept/reject boundary of :func:`is_grid_safe` and proves every
+:data:`SAFE_PALETTE` entry clears it. The acceptances include the
+East-Asian-Width *Ambiguous* CP437 glyphs the game leans on (``█ ♣ ↑ ∩ ≈ ★``),
+which render single-column under the Western monospace our surfaces use; the
+rejections are the genuinely double-width and zero-width classes that tear a
+frame.
+"""
+
+from __future__ import annotations
+
+import unicodedata
+
+import pytest
+
+from understone.engine.textwidth import SAFE_PALETTE, is_grid_safe
+from understone.world.loader import RESERVED_GLYPHS
+
+# Single-column glyphs that must be admitted: plain ASCII, a Latin accent that
+# is one composed code point, and the Ambiguous-width CP437 set the re-skin uses.
+_ACCEPTED = ["a", "Z", "ö", "☻", "≋", "█", "∩", "★", "♣", "↑", ".", "$", " "]
+
+# Must be rejected, with the reason each one trips the gate.
+_REJECTED = {
+    "龍": "wide CJK ideograph (EAW=W) — two columns",
+    "🌲": "emoji (EAW=W) — two columns",
+    "Ａ": "fullwidth Latin A (EAW=F) — two columns",
+    "é": "decomposed e + combining acute — two code points",
+    "́": "a lone combining acute — zero width",
+    "👨‍👩": "ZWJ sequence — multiple code points",
+    "ab": "two characters",
+    "": "empty string",
+    "\t": "a control character",
+}
+
+
+@pytest.mark.parametrize("ch", _ACCEPTED)
+def test_is_grid_safe_accepts(ch: str) -> None:
+    assert is_grid_safe(ch) is True
+
+
+@pytest.mark.parametrize("text", list(_REJECTED), ids=list(_REJECTED.values()))
+def test_is_grid_safe_rejects(text: str) -> None:
+    assert is_grid_safe(text) is False
+
+
+def test_safe_palette_is_all_grid_safe() -> None:
+    """Every curated palette glyph clears the gate — the appendix can't ship a dud."""
+    bad = [g for g in SAFE_PALETTE if not is_grid_safe(g)]
+    assert bad == [], f"palette has non-grid-safe glyphs: {bad}"
+
+
+def test_safe_palette_has_no_reserved_glyphs() -> None:
+    """No palette glyph is a loader-reserved marker — the 'author-usable' promise.
+
+    The appendix tells a pack author to pull any palette glyph for terrain,
+    structures, or actors, but the loader rejects the box-drawing frame lines
+    and the '@'/'☻' player markers (``loader.RESERVED_GLYPHS``). A palette entry
+    that is also reserved would hand the author a glyph that load-fails — the
+    exact doc-vs-enforcement trap. Guarding the intersection keeps "all tested
+    safe AND author-usable" enforced, not merely asserted on width.
+    """
+    collisions = set(SAFE_PALETTE) & RESERVED_GLYPHS
+    assert collisions == set(), f"palette offers loader-reserved glyphs: {sorted(collisions)}"
+
+
+def test_safe_palette_has_no_duplicates() -> None:
+    """The palette is a set in spirit; a dupe would be an authoring slip."""
+    assert len(SAFE_PALETTE) == len(set(SAFE_PALETTE))
+
+
+def test_ambiguous_width_glyphs_are_accepted() -> None:
+    """Document the load-bearing call: EAW=Ambiguous is admitted, not barred.
+
+    These are the CP437 glyphs the game depends on; if a future tightening
+    barred Ambiguous, the whole re-skin would vanish from the map.
+    """
+    for ch in "█♣↑∩≈★":
+        assert unicodedata.east_asian_width(ch) == "A"
+        assert is_grid_safe(ch) is True

examples/door-game/tests/test_turns.py

@@ -0,0 +1,94 @@
+"""Daily-turn budget and UTC rollover tests.
+
+Covers spend/refuse semantics, the lazy reset when the UTC day advances
+(including a 23:59 -> 00:01 crossing on the same Player instance), and the
+shared rollover of the bestow pool.
+"""
+
+from __future__ import annotations
+
+from tests.conftest import fixed_clock, make_player, utc
+from understone.engine.turns import ensure_day, spend_turn
+
+
+def test_spend_decrements() -> None:
+    player = make_player(turns_left=3)
+    assert spend_turn(player) is True
+    assert player.turns_left == 2
+
+
+def test_spend_refuses_at_zero_without_mutation() -> None:
+    player = make_player(turns_left=0)
+    before = player.turns_left
+    assert spend_turn(player) is False
+    assert player.turns_left == before
+
+
+def test_ensure_day_resets_on_new_day() -> None:
+    day = utc(2026, 6, 12).toordinal()
+    player = make_player(turns_left=0, turn_day=day - 1, bestow_spent=20, bestow_day=day - 1)
+    reset = ensure_day(player, fixed_clock(utc(2026, 6, 12, 9, 0)), daily_turns=10)
+    assert reset is True
+    assert player.turns_left == 10
+    assert player.turn_day == day
+    assert player.bestow_spent == 0
+    assert player.bestow_day == day
+
+
+def test_ensure_day_noop_within_same_day() -> None:
+    day = utc(2026, 6, 12).toordinal()
+    # Every day marker is already today, so no allowance (turns, bestow, posts,
+    # dice) is touched — the rollover is a pure no-op.
+    player = make_player(
+        turns_left=4,
+        turn_day=day,
+        bestow_spent=10,
+        bestow_day=day,
+        post_day=day,
+        gamble_day=day,
+    )
+    reset = ensure_day(player, fixed_clock(utc(2026, 6, 12, 23, 0)), daily_turns=10)
+    assert reset is False
+    assert player.turns_left == 4
+    assert player.bestow_spent == 10
+
+
+def test_midnight_crossing_refreshes_on_same_instance() -> None:
+    # Evening of day one: spend down to a low budget.
+    player = make_player(turns_left=10, turn_day=0, bestow_spent=0, bestow_day=0)
+    evening = utc(2026, 6, 12, 23, 59)
+    ensure_day(player, fixed_clock(evening), daily_turns=10)
+    for _ in range(8):
+        spend_turn(player)
+    assert player.turns_left == 2
+
+    # Just past midnight (UTC) the next action refreshes the budget.
+    after_midnight = utc(2026, 6, 13, 0, 1)
+    reset = ensure_day(player, fixed_clock(after_midnight), daily_turns=10)
+    assert reset is True
+    assert player.turns_left == 10
+    assert player.turn_day == after_midnight.toordinal()
+
+
+def test_bestow_pool_resets_on_the_same_boundary() -> None:
+    player = make_player(bestow_spent=25, bestow_day=utc(2026, 6, 12).toordinal())
+    ensure_day(player, fixed_clock(utc(2026, 6, 13, 0, 1)), daily_turns=10)
+    assert player.bestow_spent == 0
+    assert player.bestow_day == utc(2026, 6, 13).toordinal()
+
+
+def test_social_caps_reset_on_the_same_boundary() -> None:
+    """Posts and dice counts ride the same UTC rollover as turns and bestow."""
+    yesterday = utc(2026, 6, 12).toordinal()
+    player = make_player(
+        posts_sent=5,
+        post_day=yesterday,
+        gambles=5,
+        gamble_day=yesterday,
+    )
+    reset = ensure_day(player, fixed_clock(utc(2026, 6, 13, 0, 1)), daily_turns=10)
+    assert reset is True
+    assert player.posts_sent == 0
+    assert player.post_day == utc(2026, 6, 13).toordinal()
+    assert player.gambles == 0
+    assert player.gamble_day == utc(2026, 6, 13).toordinal()

examples/door-game/tests/test_watch.py

@@ -0,0 +1,591 @@
+"""Watch-page payload builders and the watch-URL advertisement.
+
+These are pure-unit tests of :mod:`understone.watch` (no network): the static
+world payload's shape and legend completeness, the dynamic state payload's
+player/herald/hall content under a frozen clock, and the join/help "Watch the
+Vale live" line that appears only when a Game carries a watch URL.
+"""
+
+from __future__ import annotations
+
+import re
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+import pytest
+
+from tests.conftest import fixed_clock, utc
+from understone import server as understone_server
+from understone import watch
+from understone.engine.log import Event
+from understone.engine.rng import GameRNG
+from understone.game import Game
+from understone.persistence import Store
+from understone.screen.palette import Color
+from understone.world.loader import load_world
+
+if TYPE_CHECKING:
+    from understone.engine.world import World
+
+PACK = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+
+@pytest.fixture
+def world() -> World:
+    return load_world(PACK)
+
+
+@pytest.fixture
+def clock() -> object:
+    return fixed_clock(utc(2026, 6, 12, 10, 30))
+
+
+def _game(tmp_path: Path, clock: object, watch_url: str | None = None) -> Game:
+    world = load_world(PACK)
+    store = Store(tmp_path / "watch.db")
+    return Game(  # type: ignore[arg-type]
+        world, store, clock=clock, rng=GameRNG(seed=7), watch_url=watch_url
+    )
+
+
+# ---------------------------------------------------------------------------
+# World payload (static)
+# ---------------------------------------------------------------------------
+
+
+def test_world_payload_shape(world: World) -> None:
+    payload = watch.build_world_payload(world)
+    assert payload["name"] == world.name
+    assert payload["width"] == world.width
+    assert payload["height"] == world.height
+    rows = payload["glyph_rows"]
+    assert isinstance(rows, list)
+    assert len(rows) == world.height
+    assert all(isinstance(r, str) and len(r) == world.width for r in rows)
+
+
+def test_world_payload_legend_is_complete(world: World) -> None:
+    payload = watch.build_world_payload(world)
+    rows = payload["glyph_rows"]
+    legend = payload["legend"]
+    assert isinstance(rows, list)
+    assert isinstance(legend, dict)
+    # Contract: every glyph that appears in the rows has a colour in the legend.
+    glyphs = {ch for row in rows for ch in row}
+    assert glyphs <= set(legend)
+    # And every legend colour is a real palette colour name (no stray roles).
+    valid = {c.value for c in Color}
+    assert set(legend.values()) <= valid
+
+
+def test_world_payload_locations_present(world: World) -> None:
+    payload = watch.build_world_payload(world)
+    locations = payload["locations"]
+    assert isinstance(locations, list)
+    assert len(locations) == len(world.locations)
+    by_name = {loc["name"]: loc for loc in locations}
+    # The dungeon mouth rides in the locations overlay with its glyph + colour.
+    deep = by_name["The Understone Deep"]
+    assert deep["glyph"] == "∩"
+    assert deep["color"] == "dungeon"
+    assert (deep["x"], deep["y"]) == (70, 12)
+
+
+def test_world_payload_carries_reskinned_glyphs(world: World) -> None:
+    """The v0.6 re-skin reaches the Watch: ≋ water in the rows, ⌂/✚/∩ buildings.
+
+    Water rides the base terrain (glyph_rows + legend); the buildings ride the
+    locations overlay. If a glyph reverts, the live map drifts from the frames.
+    """
+    payload = watch.build_world_payload(world)
+    rows = payload["glyph_rows"]
+    assert isinstance(rows, list)
+    glyphs = {ch for row in rows for ch in row}
+    assert "≋" in glyphs  # water in the base map
+    assert "~" not in glyphs  # the old water glyph is gone
+    legend = payload["legend"]
+    assert isinstance(legend, dict)
+    assert "≋" in legend
+    by_name = {loc["name"]: loc["glyph"] for loc in payload["locations"]}  # type: ignore[index,union-attr]
+    assert by_name["The Sleeping Drake"] == "⌂"
+    assert by_name["The Quiet Shrine"] == "✚"
+    assert by_name["The Understone Deep"] == "∩"
+
+
+# ---------------------------------------------------------------------------
+# v0.9 colour-role split — the payload now carries the EXPANDED vocabulary, so
+# distinct terrain/building types read by hue on the Watch and not just by glyph.
+# These pin the literal fixes: road no longer shares grass's colour, forest no
+# longer shares tree's, the town buildings each carry their own role, and the
+# Cinder slag is lava (orange), no longer water (blue).
+# ---------------------------------------------------------------------------
+
+CINDER = Path(__file__).resolve().parents[1] / "understone" / "world" / "packs" / "cinder-wastes"
+
+
+def _terrain_kinds(world: World) -> dict[str, str]:
+    """Return the distinct terrain kinds in *world* as ``{key: colour role}``.
+
+    ``world.terrain`` is the painted 2-D grid (one ``TerrainDef`` per cell); the
+    distinct kinds are recovered by deduplicating it on ``key``. Every kind in a
+    shipped world appears on the map, so this sees all of them.
+    """
+    kinds: dict[str, str] = {}
+    for row in world.terrain:
+        for cell in row:
+            kinds[cell.key] = cell.color
+    return kinds
+
+
+def _legend_for_terrain_key(world: World, key: str) -> str:
+    """Return the legend colour the payload carries for terrain ``key``.
+
+    Resolves the terrain key to its glyph, then reads that glyph's colour out of
+    the built payload's legend — so the assertion is on what the Watch receives,
+    not on the raw JSON.
+    """
+    payload = watch.build_world_payload(world)
+    legend = payload["legend"]
+    assert isinstance(legend, dict)
+    glyph = next(cell.glyph for row in world.terrain for cell in row if cell.key == key)
+    return legend[glyph]
+
+
+def test_vale_payload_road_is_not_floor(world: World) -> None:
+    """REGRESSION (the literal bug the slice fixes): road has its OWN colour.
+
+    Before v0.9 the Vale road shared ``floor`` with grass, so a path was
+    indistinguishable from open ground on the Watch. The road now carries
+    ``road``; grass keeps ``floor``; they must differ.
+    """
+    road = _legend_for_terrain_key(world, "road")
+    grass = _legend_for_terrain_key(world, "grass")
+    assert road == "road"
+    assert grass == "floor"
+    assert road != grass
+
+
+def test_vale_payload_forest_is_not_tree(world: World) -> None:
+    """REGRESSION: forest has its OWN colour, no longer shared with tree.
+
+    Dense forest scrub used to share ``tree`` with the tree wall, so the two
+    read identically. Forest now carries ``forest``; tree keeps ``tree``.
+    """
+    forest = _legend_for_terrain_key(world, "forest")
+    tree = _legend_for_terrain_key(world, "tree")
+    assert forest == "forest"
+    assert tree == "tree"
+    assert forest != tree
+
+
+def test_vale_payload_buildings_carry_distinct_roles(world: World) -> None:
+    """Each Vale town building rides its own role (inn/shop/healer), not ``town``."""
+    payload = watch.build_world_payload(world)
+    by_name = {loc["name"]: loc["color"] for loc in payload["locations"]}  # type: ignore[index,union-attr]
+    assert by_name["The Sleeping Drake"] == "inn"
+    assert by_name["Gravel & Sons Outfitters"] == "shop"
+    assert by_name["The Quiet Shrine"] == "healer"
+    assert by_name["The Understone Deep"] == "dungeon"
+    # No two distinct buildings share a colour role.
+    roles = list(by_name.values())
+    assert len(set(roles)) == len(roles)
+
+
+def test_cinder_payload_slag_is_lava_not_water() -> None:
+    """The Cinder slag carries ``lava`` (orange), never ``water`` (blue) again.
+
+    This is the Cinder half of the bug: molten slag shared ``water``, so the
+    lava rendered BLUE on the Watch. After the remap the legend carries ``lava``
+    and ``water`` appears NOWHERE in the Cinder payload (no water in this world).
+    """
+    cinder = load_world(CINDER)
+    payload = watch.build_world_payload(cinder)
+    legend = payload["legend"]
+    assert isinstance(legend, dict)
+    assert _legend_for_terrain_key(cinder, "slag") == "lava"
+    assert "water" not in legend.values()
+
+
+def test_cinder_payload_carries_expanded_roles() -> None:
+    """The Cinder terrain reads by hue: ash→barren, basalt→road, cinder→scrub.
+
+    Cinder-fields use ``scrub`` (dusky ember-brown), NOT ``forest`` (green) —
+    a volcanic waste must not render as lush woods. ``forest`` is for green
+    worlds; ``scrub`` is its barren counterpart.
+    """
+    cinder = load_world(CINDER)
+    assert _legend_for_terrain_key(cinder, "ash") == "barren"
+    assert _legend_for_terrain_key(cinder, "basalt") == "road"
+    assert _legend_for_terrain_key(cinder, "cinder") == "scrub"
+    legend = watch.build_world_payload(cinder)["legend"]
+    assert isinstance(legend, dict)
+    assert "forest" not in legend.values()  # no green woods in a volcanic waste
+    # Obsidian spire reuses the wall role (a rock barrier), same as caldera.
+    assert _legend_for_terrain_key(cinder, "spire") == "wall"
+    assert _legend_for_terrain_key(cinder, "caldera") == "wall"
+
+
+def test_both_worlds_terrain_roles_are_distinct_per_world() -> None:
+    """No two DISTINCT terrain types share a colour role within a world.
+
+    The point of the slice: after the remap each terrain kind reads by its own
+    hue. (A role MAY be shared by two types that are deliberately the same
+    barrier — spire/caldera both ``wall`` in Cinder — so this checks distinct
+    KEYS that map to the same role are only the intended wall pair.)
+    """
+    for world_dir, allowed_shared in (
+        (PACK, set()),
+        (CINDER, {("caldera", "spire")}),
+    ):
+        w = load_world(world_dir)
+        by_role: dict[str, list[str]] = {}
+        for key, role in _terrain_kinds(w).items():
+            by_role.setdefault(role, []).append(key)
+        for role, keys in by_role.items():
+            if len(keys) > 1:
+                pair = tuple(sorted(keys))
+                assert pair in allowed_shared, f"unexpected shared role {role!r}: {keys}"
+
+
+# ---------------------------------------------------------------------------
+# State payload (dynamic)
+# ---------------------------------------------------------------------------
+
+
+def test_state_payload_includes_joined_player(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    payload = watch.build_state_payload(game)
+    players = payload["players"]
+    assert isinstance(players, list)
+    brandr = next(p for p in players if p["name"] == "Brandr")
+    assert brandr["level"] == 1
+    assert brandr["wins"] == 0
+    assert brandr["hp"] == brandr["max_hp"]
+    assert brandr["mode"] == "tile"
+    assert (brandr["x"], brandr["y"]) == game.world.spawn
+    # v0.10: a fresh hero shows their starting gold on hand, nothing banked, and
+    # an empty satchel.
+    assert brandr["gold"] == game.world.settings.starting_gold
+    assert brandr["banked"] == 0
+    assert brandr["satchel"] == []
+
+
+def test_state_payload_surfaces_gold_banked_and_satchel(tmp_path: Path, clock: object) -> None:
+    """A joined hero with a stocked satchel and banked gold shows the right values.
+
+    The lobby TV surfaces the whole shared world, so each player's purse (gold
+    on hand + vault) and satchel stacks (name + qty, resolved via the pack) ride
+    the state payload.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    player = game.players["Brandr"]
+    player.gold = 120
+    player.banked = 300
+    game._satchel_set_stacks(player, [("iron_ore", 5), ("minor_potion", 2)])
+
+    payload = watch.build_state_payload(game)
+    brandr = next(p for p in payload["players"] if p["name"] == "Brandr")  # type: ignore[union-attr]
+    assert brandr["gold"] == 120
+    assert brandr["banked"] == 300
+    # Stacks resolve their display name from the pack, preserving stow order.
+    assert brandr["satchel"] == [
+        {"name": "Iron Ore", "qty": 5},
+        {"name": "Minor Potion", "qty": 2},
+    ]
+
+
+def test_state_payload_satchel_unknown_id_falls_back_to_raw(tmp_path: Path, clock: object) -> None:
+    """A satchel id no longer in the pack falls back to the raw id, never blank."""
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.players["Brandr"].satchel = "ghost_item:2"  # not in the pack
+
+    payload = watch.build_state_payload(game)
+    brandr = next(p for p in payload["players"] if p["name"] == "Brandr")  # type: ignore[union-attr]
+    assert brandr["satchel"] == [{"name": "ghost_item", "qty": 2}]
+
+
+def test_state_payload_reports_all_players_including_menu(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.join("Brandr")
+    game.join("Sigrun")
+    # Put Sigrun in a MENU surface; the Watch still shows her on the board.
+    sigrun = game.players["Sigrun"]
+    from understone.engine.models import Mode
+
+    sigrun.mode = Mode.MENU
+    sigrun.at_location = "inn"
+    payload = watch.build_state_payload(game)
+    names = {p["name"] for p in payload["players"]}  # type: ignore[union-attr]
+    assert names == {"Brandr", "Sigrun"}
+    menu = next(p for p in payload["players"] if p["name"] == "Sigrun")  # type: ignore[union-attr]
+    assert menu["mode"] == "menu"
+
+
+def test_state_payload_ts_comes_from_clock(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    payload = watch.build_state_payload(game)
+    assert payload["ts"] == "2026-06-12T10:30:00+00:00"
+
+
+def test_state_payload_herald_is_last_15_oldest_first(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    # Replace the resident feed with 20 synthetic events in ascending id order.
+    game.events = [
+        Event(
+            event_id=i,
+            ts=f"2026-06-12T10:{i:02d}:00+00:00",
+            kind="join",
+            actor=f"Hero{i}",
+            text=f"event {i}",
+        )
+        for i in range(1, 21)
+    ]
+    payload = watch.build_state_payload(game)
+    herald = payload["herald"]
+    assert isinstance(herald, list)
+    assert len(herald) == 15
+    # Oldest-first: the window is events 6..20, in ascending order.
+    assert herald[0]["text"] == "event 6"
+    assert herald[-1]["text"] == "event 20"
+
+
+def test_state_payload_herald_full_window_despite_sparse_ids(tmp_path: Path, clock: object) -> None:
+    """Id gaps must not shrink the feed (regression: the window is a list
+    tail, not id arithmetic — AUTOINCREMENT ids may be non-contiguous)."""
+    game = _game(tmp_path, clock)
+    game.events = [
+        Event(
+            event_id=i * 7,  # sparse, non-contiguous ids
+            ts=f"2026-06-12T10:{i:02d}:00+00:00",
+            kind="join",
+            actor=f"Hero{i}",
+            text=f"event {i}",
+        )
+        for i in range(1, 21)
+    ]
+    herald = watch.build_state_payload(game)["herald"]
+    assert len(herald) == 15
+    assert herald[0]["text"] == "event 6"
+    assert herald[-1]["text"] == "event 20"
+
+
+def test_state_payload_herald_handles_short_feed(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    game.events = [
+        Event(
+            event_id=1,
+            ts="2026-06-12T10:00:00+00:00",
+            kind="join",
+            actor="Solo",
+            text="only one",
+        )
+    ]
+    payload = watch.build_state_payload(game)
+    herald = payload["herald"]
+    assert isinstance(herald, list)
+    assert [e["text"] for e in herald] == ["only one"]
+
+
+def test_state_payload_hall_capped_at_five(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    # Seven immortalised runs; the Watch shows only the five most recent.
+    for i in range(7):
+        game.store.insert_hall_row(f"Hero{i}", f"2026-06-{10 + i:02d}T12:00:00+00:00", i, 6 + i)
+    game.store.commit()
+    payload = watch.build_state_payload(game)
+    hall = payload["hall"]
+    assert isinstance(hall, list)
+    assert len(hall) == 5
+    # Newest first (store ordering): Hero6 leads.
+    assert hall[0]["name"] == "Hero6"
+    assert hall[0]["level_at_win"] == 12
+
+
+# ---------------------------------------------------------------------------
+# Watch-URL advertisement (join banner + help manual)
+# ---------------------------------------------------------------------------
+
+
+def test_join_advertises_watch_url_when_set(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock, watch_url="http://127.0.0.1:8077/watch")
+    out = game.join("Brandr")
+    assert "Watch the Vale live: http://127.0.0.1:8077/watch" in out
+
+
+def test_join_omits_watch_line_when_unset(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock)
+    out = game.join("Brandr")
+    assert "Watch the Vale live" not in out
+
+
+def test_resume_advertises_watch_url_when_set(tmp_path: Path, clock: object) -> None:
+    game = _game(tmp_path, clock, watch_url="http://127.0.0.1:8077/watch")
+    game.join("Brandr")
+    again = game.join("Brandr")
+    assert "Welcome back" in again
+    assert "Watch the Vale live: http://127.0.0.1:8077/watch" in again
+
+
+def test_help_advertises_watch_url_when_set(tmp_path: Path) -> None:
+    # door_help reads the module game; install one carrying a watch URL.
+    world = load_world(PACK)
+    store = Store(tmp_path / "help.db")
+    understone_server._set_game(Game(world, store, watch_url="http://127.0.0.1:8077/watch"))
+    try:
+        manual = understone_server.door_help()
+        assert "Watch the Vale live: http://127.0.0.1:8077/watch" in manual
+    finally:
+        understone_server._GAME.store.close()  # type: ignore[union-attr]
+        understone_server._GAME = None
+
+
+def test_help_omits_watch_line_when_unset(tmp_path: Path) -> None:
+    world = load_world(PACK)
+    store = Store(tmp_path / "help.db")
+    understone_server._set_game(Game(world, store))
+    try:
+        manual = understone_server.door_help()
+        assert "Watch the Vale live" not in manual
+    finally:
+        understone_server._GAME.store.close()  # type: ignore[union-attr]
+        understone_server._GAME = None
+
+
+# ---------------------------------------------------------------------------
+# WATCH_HTML lockstep guards (the JS twin of texture.py + the v0.6 glow-up)
+#
+# The inline page reproduces logic that lives in Python; these guard the two
+# invariants most prone to silent drift — the texture selection formula and the
+# other-player marker — plus the presence of the day-phase machinery.
+# ---------------------------------------------------------------------------
+
+
+def test_watch_html_derives_texture_formula_from_constants() -> None:
+    """The page's JS index string is DERIVED from texture._HASH_X / _HASH_Y.
+
+    Not a hard-coded "x * 31 + y * 17" snapshot: the expected substring is built
+    from the live constants, so a Python-side retune that the watch builder
+    fails to track trips here instead of silently shipping a stale formula.
+    """
+    from understone.screen import texture
+
+    expected = f"x * {texture._HASH_X} + y * {texture._HASH_Y}"
+    assert expected in watch.WATCH_HTML
+
+
+def test_watch_html_js_selection_agrees_with_textured() -> None:
+    """The JS selection arithmetic, replayed in Python, matches ``textured``.
+
+    The page computes ``variants[(x * _HASH_X + y * _HASH_Y) % len]``. Replaying
+    that exact formula here from the SAME constants and the SAME VARIANTS rows
+    and asserting it equals ``texture.textured`` over a full screen grid proves
+    both implementations select identically — a stronger lockstep than a string
+    match, since it pins the result, not the source text.
+    """
+    from understone.screen import texture
+
+    for base, choices in texture.VARIANTS.items():
+        for x in range(24):
+            for y in range(16):
+                js_pick = choices[(x * texture._HASH_X + y * texture._HASH_Y) % len(choices)]
+                assert texture.textured(base, x, y) == js_pick
+
+
+def test_watch_html_variants_match_texture_table() -> None:
+    """Every base->variants row in texture.VARIANTS appears in the JS VARIANTS map.
+
+    Glyphs ride into the inline JS as ``\\uXXXX`` escapes, so compare against the
+    escaped form. A new variant added to Python but not the page trips this.
+    """
+    from understone.screen import texture
+
+    html = watch.WATCH_HTML
+    for base, choices in texture.VARIANTS.items():
+        for glyph in {base, *choices}:
+            token = glyph if glyph.isascii() else f"\\u{ord(glyph):04x}"
+            assert token in html, f"variant glyph {glyph!r} missing from WATCH_HTML"
+
+
+def test_watch_html_uses_other_player_marker() -> None:
+    """Players on the lobby TV wear the ☻ marker (escaped) — no bare '@' marker paint."""
+    assert "\\u263b" in watch.WATCH_HTML
+
+
+def test_watch_html_renders_gold_banked_and_satchel() -> None:
+    """The Adventurers panel JS references each player's gold, vault, and satchel."""
+    html = watch.WATCH_HTML
+    # The roster sub-lines read these state fields by name.
+    assert "p.gold" in html
+    assert "p.banked" in html
+    assert "p.satchel" in html
+    # The satchel line has a dedicated renderer with an empty-bag note.
+    assert "satchelText" in html
+    assert "satchel empty" in html
+    assert "vault" in html
+
+
+def test_watch_html_has_day_phase_machinery() -> None:
+    """The dusk/dawn glow-up is wired: the tint classes and the UTC-hour read."""
+    html = watch.WATCH_HTML
+    assert "applyDayPhase" in html
+    assert "getUTCHours" in html
+    assert ".map-frame.night" in html
+    assert ".map-frame.twilight" in html
+    assert "Noto Sans Mono" in html
+
+
+# ---------------------------------------------------------------------------
+# PALETTE completeness — the v0.9 invariant that kills the "silent fallback"
+# bug class. The road bug existed because a Color role with no hex in the JS
+# PALETTE map fell back to default; this pins that EVERY role has a hex.
+# ---------------------------------------------------------------------------
+
+
+def _watch_palette_keys() -> set[str]:
+    """Parse the JS ``var PALETTE = { ... }`` map out of WATCH_HTML, return its keys.
+
+    The map uses bare (unquoted) JS identifier keys — ``road: "#b89a6a",`` — so
+    this slices the object literal and collects every ``key:`` token. Keeping the
+    parse here (not a hard-coded list) means the test reads whatever the page
+    actually ships, so a typo'd or dropped key surfaces as a missing role.
+    """
+    html = watch.WATCH_HTML
+    start = html.index("var PALETTE = {")
+    body = html[start : html.index("};", start)]
+    # Each entry is `<ident>: "<hex>"`; capture the identifier before the colon.
+    return set(re.findall(r"(\w+)\s*:\s*\"#", body))
+
+
+def test_watch_palette_covers_every_color_role() -> None:
+    """EVERY Color enum value has an entry in the JS PALETTE map — no fallbacks.
+
+    This is the literal fix for the road bug: a shipped role with no hex paints
+    as ``default`` silently. Asserting ``{c.value} <= palette_keys`` means adding
+    a Color without a Watch hex trips here instead of shipping a grey/green road.
+    """
+    palette_keys = _watch_palette_keys()
+    roles = {c.value for c in Color}
+    missing = roles - palette_keys
+    assert not missing, f"Color roles with no PALETTE hex (silent fallback): {sorted(missing)}"
+
+
+def test_watch_palette_distinct_new_terrain_hexes() -> None:
+    """The expanded terrain roles carry DISTINCT hexes (the point of the slice).
+
+    A guard that the seven new roles didn't accidentally collapse onto one hex
+    (which would re-introduce the very "two types, one colour" bug v0.9 fixes).
+    Parsed straight from the shipped map.
+    """
+    html = watch.WATCH_HTML
+    start = html.index("var PALETTE = {")
+    body = html[start : html.index("};", start)]
+    pairs = dict(re.findall(r"(\w+)\s*:\s*\"(#[0-9a-fA-F]{6})\"", body))
+    new_roles = ["road", "forest", "lava", "barren", "inn", "shop", "healer"]
+    hexes = [pairs[r] for r in new_roles]
+    assert all(r in pairs for r in new_roles), "a new v0.9 role is missing its hex"
+    assert len(set(hexes)) == len(hexes), f"new roles share a hex: {hexes}"
+    # The molten role must NOT reuse water's blue (the Cinder slag bug).
+    assert pairs["lava"] != pairs["water"]

examples/door-game/tests/test_watch_theme.py

@@ -0,0 +1,143 @@
+"""Tests for the per-pack Watch CRT theme (v0.8).
+
+Covers the loader band (each of the four legal themes loads; an unknown theme
+is rejected naming the legal set; an omitted theme defaults to phosphor), the
+state-payload carrying the theme, and the WATCH_HTML page's JS THEME table —
+including the load-bearing guard that the "phosphor" values byte-match the
+original ``:root`` CSS, so the bundled Vale stays visually identical.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+from pathlib import Path
+from typing import Any
+
+import pytest
+
+from understone import watch
+from understone.errors import WorldLoadError
+from understone.world.loader import (
+    DEFAULT_WATCH_THEME,
+    WATCH_THEMES,
+    load_world,
+)
+
+SHIPPED = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+# The original :root CRT custom-property values (pre-v0.8). The "phosphor" theme
+# MUST reproduce these byte-for-byte so the default Vale is pixel-identical.
+_ORIGINAL_ROOT = {
+    "--phosphor": "#7dffa0",
+    "--phosphor-dim": "#2f7a46",
+    "--amber": "#ffb44d",
+    "--bg": "#050a06",
+    "--panel": "#0a140d",
+    "--edge": "#163a22",
+}
+
+
+def _pack_with_theme(tmp_path: Path, theme: Any) -> Path:
+    """Clone the Vale into a temp pack with ``settings.watch_theme`` set/removed.
+
+    ``theme`` set to a string writes that value; set to the sentinel ``...``
+    DELETES the key entirely (to exercise the omitted-defaults path).
+    """
+    dest = tmp_path / "themed"
+    shutil.copytree(SHIPPED, dest)
+    world_json = dest / "world.json"
+    data = json.loads(world_json.read_text(encoding="utf-8"))
+    if theme is ...:
+        data["settings"].pop("watch_theme", None)
+    else:
+        data["settings"]["watch_theme"] = theme
+    world_json.write_text(json.dumps(data), encoding="utf-8")
+    return dest
+
+
+# ---------------------------------------------------------------------------
+# loader band
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.parametrize("theme", sorted(WATCH_THEMES))
+def test_each_legal_theme_loads(tmp_path: Path, theme: str) -> None:
+    pack = _pack_with_theme(tmp_path, theme)
+    world = load_world(pack)
+    assert world.settings.watch_theme == theme
+
+
+def test_unknown_theme_rejected_naming_the_set(tmp_path: Path) -> None:
+    pack = _pack_with_theme(tmp_path, "ultraviolet")
+    with pytest.raises(WorldLoadError) as exc:
+        load_world(pack)
+    message = str(exc.value)
+    assert "watch_theme" in message
+    assert "ultraviolet" in message
+    # The friendly message lists every legal theme so the author can fix it.
+    for name in WATCH_THEMES:
+        assert name in message
+
+
+def test_omitted_theme_defaults_to_phosphor(tmp_path: Path) -> None:
+    pack = _pack_with_theme(tmp_path, ...)  # delete the key entirely
+    world = load_world(pack)
+    assert world.settings.watch_theme == DEFAULT_WATCH_THEME == "phosphor"
+
+
+def test_shipped_vale_is_phosphor() -> None:
+    """The bundled Vale ships the phosphor theme (its green is unchanged)."""
+    world = load_world(SHIPPED)
+    assert world.settings.watch_theme == "phosphor"
+
+
+# ---------------------------------------------------------------------------
+# payload + WATCH_HTML
+# ---------------------------------------------------------------------------
+
+
+def test_world_payload_carries_theme(tmp_path: Path) -> None:
+    pack = _pack_with_theme(tmp_path, "ice")
+    world = load_world(pack)
+    payload = watch.build_world_payload(world)
+    assert payload["theme"] == "ice"
+
+
+def test_shipped_payload_theme_is_phosphor() -> None:
+    world = load_world(SHIPPED)
+    payload = watch.build_world_payload(world)
+    assert payload["theme"] == "phosphor"
+
+
+def test_watch_html_has_theme_table_and_all_names() -> None:
+    """The page carries a JS THEME table keyed by every legal theme name."""
+    html = watch.WATCH_HTML
+    assert "var THEMES" in html
+    assert "applyTheme" in html
+    for name in WATCH_THEMES:
+        # Each theme is a JS object key, e.g. ``phosphor: {``.
+        assert f"{name}: {{" in html, f"theme {name!r} missing from THEME table"
+
+
+def test_watch_html_phosphor_values_byte_match_original_root() -> None:
+    """The "phosphor" theme reproduces the original :root values exactly.
+
+    This is the load-bearing guard for "the Vale looks identical": every
+    original custom-property value still appears in the page (in the :root block
+    AND the THEME table), so swapping in the phosphor theme is a no-op repaint.
+    """
+    html = watch.WATCH_HTML
+    for prop, value in _ORIGINAL_ROOT.items():
+        # The value lives both in the :root CSS and the phosphor theme entry.
+        assert html.count(value) >= 2, f"{prop} value {value} not byte-matched twice"
+        # And the phosphor theme maps the property to exactly that value.
+        assert f'"{prop}": "{value}"' in html, f"phosphor {prop} != {value}"
+
+
+def test_watch_html_applies_theme_on_world_fetch() -> None:
+    """The page applies the theme when world.json arrives (in paintMap)."""
+    html = watch.WATCH_HTML
+    assert "applyTheme(world.theme)" in html
+    # It swaps CSS custom properties on the document root.
+    assert "documentElement.style.setProperty" in html

examples/door-game/tests/test_world_loader.py

@@ -0,0 +1,851 @@
+"""Content-pack loader tests.
+
+Asserts the shipped pack loads, and that representative malformed packs
+each raise :class:`WorldLoadError` with a readable message: a bad legend
+character, a location placed on non-walkable terrain, a row-width / height
+mismatch, and an economy setting outside its sanity band.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+from pathlib import Path
+from typing import Any
+
+import pytest
+
+from understone.errors import WorldLoadError
+from understone.world.loader import load_world
+
+SHIPPED = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+
+def test_shipped_pack_loads() -> None:
+    world = load_world(SHIPPED)
+    assert world.name == "The Vale of Understone"
+    assert world.width == 96
+    assert world.height == 48
+    assert world.is_walkable(*world.spawn)
+    assert len(world.locations) == 4
+    assert len(world.zones) == 2
+    # Tiers 1..5 are the random foes; tier 6 is the boss (the Wyrm Below).
+    assert {m.tier for m in world.monsters} == {1, 2, 3, 4, 5, 6}
+    boss = world.monster_by_id(world.settings.boss_monster)
+    assert boss is not None and boss.boss and boss.name == "the Wyrm Below"
+
+
+def _clone_pack(tmp_path: Path) -> Path:
+    dest = tmp_path / "pack"
+    shutil.copytree(SHIPPED, dest)
+    return dest
+
+
+def _rewrite(path: Path, mutate: Any) -> None:
+    data = json.loads(path.read_text(encoding="utf-8"))
+    mutate(data)
+    path.write_text(json.dumps(data), encoding="utf-8")
+
+
+def test_bad_legend_char_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        # Splice an unknown glyph into the middle of a terrain row.
+        row = list(data["terrain_rows"][24])
+        row[40] = "Z"
+        data["terrain_rows"][24] = "".join(row)
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="not in the legend"):
+        load_world(pack)
+
+
+def test_location_on_non_walkable_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        # Move the inn onto a tree-border tile (col 0 is the tree frame).
+        for loc in data["locations"]:
+            if loc["key"] == "inn":
+                loc["x"] = 0
+                loc["y"] = 24
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="non-walkable"):
+        load_world(pack)
+
+
+def test_dimension_mismatch_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        # Truncate one row so its width no longer matches the declared width.
+        data["terrain_rows"][10] = data["terrain_rows"][10][:-5]
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="wide but width is"):
+        load_world(pack)
+
+
+def test_height_mismatch_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["terrain_rows"] = data["terrain_rows"][:-1]
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="rows but height is"):
+        load_world(pack)
+
+
+def test_settings_out_of_band_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["daily_turns"] = 0  # band is 1..100
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="daily_turns"):
+        load_world(pack)
+
+
+def test_start_hp_zero_rejected(tmp_path: Path) -> None:
+    """A starting HP of 0 is out of band (1..500): a hero must begin alive."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["start_hp"] = 0  # band is 1..500
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="start_hp"):
+        load_world(pack)
+
+
+def test_unknown_starting_item_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["starting_weapon"] = "no_such_blade"
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="not a known item id"):
+        load_world(pack)
+
+
+def test_missing_pack_file_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+    (pack / "monsters.json").unlink()
+    with pytest.raises(WorldLoadError, match="missing pack file"):
+        load_world(pack)
+
+
+def test_monster_nonpositive_hp_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        data[0]["hp"] = 0  # a monster with no hit points is unkillable nonsense
+
+    _rewrite(pack / "monsters.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"monsters\.json\[0\] hp must be >= 1"):
+        load_world(pack)
+
+
+def test_monster_negative_stat_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        data[1]["gold"] = -5
+
+    _rewrite(pack / "monsters.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"monsters\.json\[1\] gold must be >= 0"):
+        load_world(pack)
+
+
+def test_item_negative_price_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        data[1]["price"] = -10  # a negative price would pay the player to take it
+
+    _rewrite(pack / "items.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"items\.json\[1\] price must be >= 0"):
+        load_world(pack)
+
+
+def test_dungeon_tier_without_monster_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        # Tier 9 has no monster in the pack, so the gauntlet rung is unfillable.
+        data["settings"]["dungeon_tiers"] = [4, 9]
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"dungeon_tiers\[1\] = 9 has no non-boss monster"):
+        load_world(pack)
+
+
+def test_dungeon_tiers_empty_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["dungeon_tiers"] = []
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="dungeon_tiers must be a non-empty list"):
+        load_world(pack)
+
+
+def test_dungeon_tier_backed_only_by_boss_rejected(tmp_path: Path) -> None:
+    """A boss-only tier is unfillable: the gauntlet excludes boss monsters.
+
+    Tier 6 in the shipped pack holds only the Wyrm Below (a boss). A gauntlet
+    rung at tier 6 would draw from monsters_for_tier_band, which filters bosses
+    out, so the rung silently does nothing — the loader must reject it instead.
+    The message says "no NON-boss monster" (not merely "no monster"): the boss
+    is present at that tier, it just cannot fill a rung, and the wording must
+    point the author at exactly that.
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["dungeon_tiers"] = [4, 6]  # 6 is the boss-only tier
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"dungeon_tiers\[1\] = 6 has no non-boss monster"):
+        load_world(pack)
+
+
+# ---------------------------------------------------------------------------
+# v0.2 loader rejections: the event table and the Wyrm settings
+# ---------------------------------------------------------------------------
+
+
+def test_events_without_fight_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        # Strip every fight row; a walk could then never spawn a monster.
+        data["events"] = [e for e in data["events"] if e["kind"] != "fight"]
+
+    _rewrite(pack / "events.json", mutate)
+    with pytest.raises(WorldLoadError, match="at least one 'fight' entry"):
+        load_world(pack)
+
+
+def test_event_zero_weight_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["events"][0]["weight"] = 0
+
+    _rewrite(pack / "events.json", mutate)
+    with pytest.raises(WorldLoadError, match="weight must be > 0"):
+        load_world(pack)
+
+
+def test_event_min_exceeds_max_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        # Find a value-bearing row and invert its band.
+        for event in data["events"]:
+            if event["kind"] == "gold":
+                event["min"], event["max"] = 9, 2
+                break
+
+    _rewrite(pack / "events.json", mutate)
+    with pytest.raises(WorldLoadError, match="min 9 exceeds max 2"):
+        load_world(pack)
+
+
+def test_event_amount_out_of_band_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        for event in data["events"]:
+            if event["kind"] == "heal":
+                event["max"] = 500  # heal band is 1..100
+                break
+
+    _rewrite(pack / "events.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"heal amount .* is out of band"):
+        load_world(pack)
+
+
+def test_event_nonfight_blank_text_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        for event in data["events"]:
+            if event["kind"] == "lore":
+                event["text"] = "   "
+                break
+
+    _rewrite(pack / "events.json", mutate)
+    with pytest.raises(WorldLoadError, match="requires non-empty 'text'"):
+        load_world(pack)
+
+
+def test_boss_monster_unknown_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["boss_monster"] = "no_such_wyrm"
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="is not a known monster id"):
+        load_world(pack)
+
+
+def test_boss_monster_not_flagged_boss_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        # Give a plain monster an id and point boss_monster at it; it lacks the
+        # boss flag, so it must be rejected as the endgame foe.
+        data[0]["id"] = "field_rat"
+
+    _rewrite(pack / "monsters.json", mutate)
+
+    def point(data: dict[str, Any]) -> None:
+        data["settings"]["boss_monster"] = "field_rat"
+
+    _rewrite(pack / "world.json", point)
+    with pytest.raises(WorldLoadError, match='must be flagged "boss": true'):
+        load_world(pack)
+
+
+def test_wyrm_min_level_out_of_band_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["wyrm_min_level"] = 0  # band is 1..50
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="wyrm_min_level"):
+        load_world(pack)
+
+
+# ---------------------------------------------------------------------------
+# v0.5 social settings: ambush / post / gamble economy bands
+# ---------------------------------------------------------------------------
+
+
+def test_ambush_gold_pct_out_of_band_rejected(tmp_path: Path) -> None:
+    """The steal percentage is a 0..100 band; 101 is rejected by name."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["ambush_gold_pct"] = 101  # band is 0..100
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="ambush_gold_pct"):
+        load_world(pack)
+
+
+def test_ambush_level_band_out_of_band_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["ambush_level_band"] = 11  # band is 0..10
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="ambush_level_band"):
+        load_world(pack)
+
+
+def test_gamble_max_bet_out_of_band_rejected(tmp_path: Path) -> None:
+    """A max bet of 0 is below the 1..10000 floor: the house needs a real stake."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["gamble_max_bet"] = 0  # band is 1..10000
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="gamble_max_bet"):
+        load_world(pack)
+
+
+def test_post_daily_cap_out_of_band_rejected(tmp_path: Path) -> None:
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["post_daily_cap"] = 51  # band is 0..50
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="post_daily_cap"):
+        load_world(pack)
+
+
+def test_missing_social_setting_rejected(tmp_path: Path) -> None:
+    """A pack that predates the social settings fails loudly (no silent default)."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        del data["settings"]["ambush_min_level"]
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="ambush_min_level"):
+        load_world(pack)
+
+
+# ---------------------------------------------------------------------------
+# v0.4 loader hardening: glyphs, map size, count caps, and name lengths
+#
+# Packs are now routinely untrusted LLM output, so the loader bands the shapes
+# that could tear a frame, balloon memory, or impersonate a player. Each
+# rejection still names the file and field at fault.
+# ---------------------------------------------------------------------------
+
+
+def test_box_drawing_terrain_glyph_rejected(tmp_path: Path) -> None:
+    """A terrain glyph may not be a frame box-drawing line (it would tear borders)."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["."]["glyph"] = "─"  # the horizontal frame run
+
+    _rewrite(pack / "terrain.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"terrain\.json.* box-drawing"):
+        load_world(pack)
+
+
+def test_player_marker_terrain_glyph_rejected(tmp_path: Path) -> None:
+    """A terrain glyph may not be '@' — that is the player's own marker."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["."]["glyph"] = "@"
+
+    _rewrite(pack / "terrain.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"terrain\.json.* reserved for player markers"):
+        load_world(pack)
+
+
+def test_other_player_marker_terrain_glyph_rejected(tmp_path: Path) -> None:
+    """A terrain glyph may not be '☻' — the v0.6 other-player marker."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["."]["glyph"] = "☻"
+
+    _rewrite(pack / "terrain.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"terrain\.json.* reserved for player markers"):
+        load_world(pack)
+
+
+def test_ampersand_terrain_glyph_now_accepted(tmp_path: Path) -> None:
+    """'&' is no longer an actor marker (☻ took that role), so it is pack-legal.
+
+    The load itself is the assertion — it must not raise the actor-marker
+    rejection. A grass cell then carries the new glyph.
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["."]["glyph"] = "&"
+
+    _rewrite(pack / "terrain.json", mutate)
+    world = load_world(pack)  # no WorldLoadError: '&' is admitted
+    grass = next(
+        world.terrain_at(x, y)
+        for y in range(world.height)
+        for x in range(world.width)
+        if world.terrain_at(x, y).key == "grass"
+    )
+    assert grass.glyph == "&"
+
+
+def test_wide_cjk_terrain_glyph_rejected(tmp_path: Path) -> None:
+    """A Wide (EAW=W) ideograph would render two columns and tear the frame."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["."]["glyph"] = "龍"
+
+    _rewrite(pack / "terrain.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"terrain\.json.* exactly one column"):
+        load_world(pack)
+
+
+def test_fullwidth_terrain_glyph_rejected(tmp_path: Path) -> None:
+    """A Fullwidth (EAW=F) Latin letter is two columns and is rejected."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["."]["glyph"] = "Ａ"  # U+FF21 FULLWIDTH LATIN CAPITAL LETTER A
+
+    _rewrite(pack / "terrain.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"terrain\.json.* exactly one column"):
+        load_world(pack)
+
+
+def test_reskinned_shipped_pack_glyphs() -> None:
+    """The shipped pack carries the v0.6 re-skin and still loads cleanly.
+
+    The load-bearing guard for the re-skin: water is ≋ and the three lettered
+    buildings became ⌂/✚/∩. If a data edit reverts a glyph, this trips.
+    """
+    world = load_world(SHIPPED)
+    waters = {
+        world.terrain_at(x, y).glyph
+        for y in range(world.height)
+        for x in range(world.width)
+        if world.terrain_at(x, y).key == "water"
+    }
+    assert waters == {"≋"}
+    by_key = {loc.key: loc.glyph for loc in world.locations}
+    assert by_key["inn"] == "⌂"
+    assert by_key["healer"] == "✚"
+    assert by_key["dungeon"] == "∩"
+    assert by_key["shop"] == "$"  # the shop glyph is unchanged
+
+
+def test_multichar_location_glyph_rejected(tmp_path: Path) -> None:
+    """A location glyph must be exactly one character."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["inn"]["glyph"] = "In"  # two characters
+
+    _rewrite(pack / "locations.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"locations\.json.* single character"):
+        load_world(pack)
+
+
+def test_oversized_map_rejected(tmp_path: Path) -> None:
+    """A 300x300 map is past the dimension ceiling (8..256)."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["width"] = 300
+        data["height"] = 300
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"world\.json width = 300 is out of band"):
+        load_world(pack)
+
+
+def test_too_many_events_rejected(tmp_path: Path) -> None:
+    """An event table over the 500-row cap is rejected before it is decoded."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        filler = {"kind": "lore", "weight": 1, "text": "filler"}
+        data["events"] = [filler.copy() for _ in range(501)]
+
+    _rewrite(pack / "events.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"events\.json defines 501 events; the limit is 500"):
+        load_world(pack)
+
+
+def test_overlong_monster_name_rejected(tmp_path: Path) -> None:
+    """A 49-character monster name is one past the 48-char display limit."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        data[0]["name"] = "x" * 49
+
+    _rewrite(pack / "monsters.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"monsters\.json\[0\] name is 49 characters"):
+        load_world(pack)
+
+
+# ---------------------------------------------------------------------------
+# v0.7 loader rejections: the satchel/forge bands, rare_drop_item, monster weight
+# ---------------------------------------------------------------------------
+
+
+def test_rare_drop_item_unknown_rejected(tmp_path: Path) -> None:
+    """A rare_drop_item that names no item is rejected with the item-id message."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["rare_drop_item"] = "no_such_draught"
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="rare_drop_item = 'no_such_draught' is not a known"):
+        load_world(pack)
+
+
+def test_rare_drop_item_non_consumable_rejected(tmp_path: Path) -> None:
+    """A rare_drop_item that names a weapon (not a consumable) is rejected.
+
+    The drop goes straight into the satchel to be quaffed, so a weapon or
+    armour id is incoherent — the loader pins the slot.
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["rare_drop_item"] = "iron_sword"  # a weapon, not a draught
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="rare_drop_item = 'iron_sword' must be a consumable"):
+        load_world(pack)
+
+
+def test_satchel_max_out_of_band_rejected(tmp_path: Path) -> None:
+    """satchel_max above its 1..10 band is a load error."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["satchel_max"] = 11
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"satchel_max = 11 is out of band \(1\.\.10\)"):
+        load_world(pack)
+
+
+def test_forge_max_plus_out_of_band_rejected(tmp_path: Path) -> None:
+    """forge_max_plus above its 0..10 band is a load error."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["forge_max_plus"] = 11
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"forge_max_plus = 11 is out of band \(0\.\.10\)"):
+        load_world(pack)
+
+
+def test_forge_base_cost_out_of_band_rejected(tmp_path: Path) -> None:
+    """forge_base_cost below its floor of 1 is a load error."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["forge_base_cost"] = 0
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"forge_base_cost = 0 is out of band \(1\.\.10000\)"):
+        load_world(pack)
+
+
+def test_forge_ore_item_unknown_rejected(tmp_path: Path) -> None:
+    """A forge_ore_item that names no item is rejected with the item-id message."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["forge_ore_item"] = "no_such_ore"
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="forge_ore_item = 'no_such_ore' is not a known"):
+        load_world(pack)
+
+
+def test_forge_ore_item_non_material_rejected(tmp_path: Path) -> None:
+    """A forge_ore_item that names a non-material (a potion) is rejected.
+
+    Ore is carried in the satchel and spent at the forge, never equipped or
+    quaffed, so a consumable/weapon/armour id is incoherent — the loader pins
+    the slot to ``material`` (mirroring the rare_drop_item consumable check).
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["forge_ore_item"] = "greater_potion"  # a draught, not ore
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(
+        WorldLoadError, match="forge_ore_item = 'greater_potion' must be a material"
+    ):
+        load_world(pack)
+
+
+def test_forge_ore_per_plus_out_of_band_rejected(tmp_path: Path) -> None:
+    """forge_ore_per_plus above its 0..10 band is a load error."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["forge_ore_per_plus"] = 11
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"forge_ore_per_plus = 11 is out of band \(0\.\.10\)"):
+        load_world(pack)
+
+
+def test_ore_dungeon_drop_out_of_band_rejected(tmp_path: Path) -> None:
+    """ore_dungeon_drop above its 0..20 band is a load error."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["ore_dungeon_drop"] = 21
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"ore_dungeon_drop = 21 is out of band \(0\.\.20\)"):
+        load_world(pack)
+
+
+def test_ore_forest_chance_out_of_band_rejected(tmp_path: Path) -> None:
+    """ore_forest_chance outside 0.0..1.0 is a load error (it is a probability)."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        data["settings"]["ore_forest_chance"] = 1.5
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(
+        WorldLoadError, match=r"ore_forest_chance = 1.5 is out of band \(0.0..1.0\)"
+    ):
+        load_world(pack)
+
+
+def test_monster_zero_weight_rejected(tmp_path: Path) -> None:
+    """A monster weight of 0 is rejected (the weighted pick needs a positive total)."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        data[0]["weight"] = 0
+
+    _rewrite(pack / "monsters.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"monsters\.json\[0\] weight must be > 0"):
+        load_world(pack)
+
+
+def test_shipped_pack_carries_rares_and_weights() -> None:
+    """The shipped pack parses the v0.7 rare beasts with their low weights."""
+    world = load_world(SHIPPED)
+    rares = [m for m in world.monsters if m.rare]
+    names = {m.name for m in rares}
+    assert names == {"the Gilded Stag", "the Hollow Knight"}
+    assert all(m.weight == 1 for m in rares)  # rares surface seldom
+    # The rare_drop_item resolves to a consumable.
+    drop = world.item_by_id(world.settings.rare_drop_item)
+    assert drop is not None and drop.slot.value == "consumable"
+    # The new economy settings land on their shipped values.
+    assert world.settings.satchel_max == 3
+    assert world.settings.forge_base_cost == 60
+    assert world.settings.forge_max_plus == 3
+    assert world.settings.dungeon_tiers == (3, 4, 5)
+    # v0.10 ore-forge settings resolve, and the forge ore is a material item.
+    assert world.settings.forge_ore_item == "iron_ore"
+    ore = world.item_by_id(world.settings.forge_ore_item)
+    assert ore is not None and ore.slot.value == "material"
+    assert world.settings.forge_ore_per_plus == 1
+    assert world.settings.ore_dungeon_drop == 2
+    assert world.settings.ore_forest_chance == 0.2
+
+
+def test_monster_weight_and_rare_default_when_omitted(tmp_path: Path) -> None:
+    """A monster spec without weight/rare loads as weight 10, rare False.
+
+    Both fields are optional with defaults, so an unannotated common monster
+    (the shipped Field Rat) parses to the default weight and the non-rare flag.
+    """
+    world = load_world(SHIPPED)
+    rat = next(m for m in world.monsters if m.name == "Field Rat")
+    assert rat.weight == 10  # the default biasing weight
+    assert rat.rare is False
+
+
+# ---------------------------------------------------------------------------
+# v0.8 loader hardening: rare-as-rung-guardian and the single-boss invariant
+#
+# AUTHORING states both as rules; v0.8 makes them machine-checked. A rare in
+# the lead slot of a dungeon tier would be silently promoted to a fixed rung
+# guardian (and pulled from the rare pool); a stray second boss would validate
+# clean yet make "the one endgame foe" a lie.
+# ---------------------------------------------------------------------------
+
+
+def test_rare_as_first_dungeon_tier_monster_rejected(tmp_path: Path) -> None:
+    """A rare in the FIRST slot of a dungeon tier becomes a fixed guardian — rejected.
+
+    Tier 3 backs a ``dungeon_tiers`` rung and its first monster (the Forest
+    Wolf) is the rung guardian (``band[0]``). Flagging that lead monster rare
+    would quietly turn the rare into the fixed, repeatable guardian and remove
+    it from the weighted rare roll, so the loader rejects it by name.
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        wolf = next(m for m in data if m["name"] == "Forest Wolf")  # first tier-3
+        wolf["rare"] = True
+
+    _rewrite(pack / "monsters.json", mutate)
+    with pytest.raises(
+        WorldLoadError,
+        match=r"'Forest Wolf' is rare but is the first tier-3 monster.*fixed guardian",
+    ):
+        load_world(pack)
+
+
+def test_rare_after_guardian_in_dungeon_tier_accepted(tmp_path: Path) -> None:
+    """A rare placed AFTER the guardian in the same dungeon tier loads cleanly.
+
+    The shipped pack already does exactly this (the Hollow Knight is the third
+    tier-3 entry, behind the Forest Wolf guardian). Inserting another rare also
+    after the guardian must not trip the new check — only the LEAD slot of a
+    dungeon tier is constrained.
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        # Splice a second tier-3 rare in just before the boss (well after the
+        # tier-3 guardian), so the tier's first non-boss monster is unchanged.
+        extra = {
+            "tier": 3,
+            "name": "the Ashen Stalker",
+            "hp": 26,
+            "atk": 10,
+            "def": 3,
+            "xp": 55,
+            "gold": 75,
+            "weight": 1,
+            "rare": True,
+        }
+        data.insert(len(data) - 1, extra)
+
+    _rewrite(pack / "monsters.json", mutate)
+    world = load_world(pack)  # no WorldLoadError: the rare is not the lead foe
+    tier3 = world.monsters_for_tier_band(3, 3)
+    assert tier3[0].name == "Forest Wolf"  # the guardian is still the non-rare lead
+    assert any(m.name == "the Ashen Stalker" and m.rare for m in tier3)
+
+
+def test_two_bosses_rejected(tmp_path: Path) -> None:
+    """Two ``boss``-flagged monsters are rejected: a world has exactly one boss."""
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: list[dict[str, Any]]) -> None:
+        # Give the Field Rat the boss flag too; now two monsters claim the role.
+        rat = next(m for m in data if m["name"] == "Field Rat")
+        rat["boss"] = True
+        rat["id"] = "field_rat"
+
+    _rewrite(pack / "monsters.json", mutate)
+    with pytest.raises(WorldLoadError, match=r"flags 2 monsters as .boss.* true"):
+        load_world(pack)
+
+
+def test_single_boss_accepted() -> None:
+    """The shipped pack carries exactly one boss and loads — the single-boss path.
+
+    The positive half of the invariant: the Wyrm Below is the only boss, so the
+    load succeeds and the boss count is exactly one.
+    """
+    world = load_world(SHIPPED)
+    bosses = [m for m in world.monsters if m.boss]
+    assert len(bosses) == 1
+    assert bosses[0].name == "the Wyrm Below"
+
+
+def test_overlapping_zones_rejected(tmp_path: Path) -> None:
+    """Overlapping zone rectangles are a load error.
+
+    ``zone_for`` returns the FIRST matching zone, so two zones sharing any cell
+    would silently shadow one tier band there — exactly the bug a cold-authored
+    pack shipped (a 1-column caldera-edge strip dropped to the low band). Pull
+    the deep zone west so its rect overlaps the near zone and confirm the loader
+    refuses it rather than loading the ambiguity.
+    """
+    pack = _clone_pack(tmp_path)
+
+    def mutate(data: dict[str, Any]) -> None:
+        for zone in data["zones"]:
+            if zone["key"] == "dungeon_deep":
+                zone["rect"][0] = 50  # now overlaps forest_near's x30..60 strip
+
+    _rewrite(pack / "world.json", mutate)
+    with pytest.raises(WorldLoadError, match="overlap"):
+        load_world(pack)

examples/door-game/tests/test_worlds.py

@@ -0,0 +1,206 @@
+"""Tests for bundled-world discovery and the ``worlds`` listing.
+
+Covers the discovery helper (the Vale leads, alternate packs follow
+alphabetically, non-pack directories are skipped) and the ``cli_worlds``
+listing it backs: a sound fixture pack reports "sound", a deliberately-flawed
+fixture pack reports "flawed", and the Vale is always listed first. The
+``packs/`` directory is monkeypatched to a temp fixture tree so these tests
+never depend on the real (separately-authored) second world.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+from io import StringIO
+from pathlib import Path
+from typing import TYPE_CHECKING, Any
+
+from understone import cli
+from understone import world as world_pkg
+from understone.world import VALE_SLUG, bundled_world_dirs
+
+if TYPE_CHECKING:
+    import pytest
+
+SHIPPED = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+
+def _make_packs(tmp_path: Path, *, sound: list[str], flawed: dict[str, Any]) -> Path:
+    """Build a temp ``packs/`` tree: sound slugs plus flawed-world slugs.
+
+    Each sound slug is a verbatim copy of the shipped Vale; each flawed slug is
+    a copy whose ``world.json`` is patched with the given settings overrides so
+    it fails to load. Returns the packs root to monkeypatch ``PACKS_DIR`` onto.
+    """
+    packs = tmp_path / "packs"
+    packs.mkdir()
+    for slug in sound:
+        shutil.copytree(SHIPPED, packs / slug)
+    for slug, overrides in flawed.items():
+        dest = packs / slug
+        shutil.copytree(SHIPPED, dest)
+        world_json = dest / "world.json"
+        data = json.loads(world_json.read_text(encoding="utf-8"))
+        data["settings"].update(overrides)
+        world_json.write_text(json.dumps(data), encoding="utf-8")
+    return packs
+
+
+# ---------------------------------------------------------------------------
+# bundled_world_dirs discovery
+# ---------------------------------------------------------------------------
+
+
+def test_bundled_world_dirs_vale_leads_then_alpha(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    packs = _make_packs(tmp_path, sound=["zephyr", "ashfall"], flawed={})
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", packs)
+
+    found = bundled_world_dirs()
+    slugs = [slug for slug, _ in found]
+    # The Vale is always first; alternates follow alphabetically.
+    assert slugs == [VALE_SLUG, "ashfall", "zephyr"]
+    # The Vale entry points at the packaged data dir, not a packs subdir.
+    assert found[0][1] == world_pkg.PACKAGED_WORLD_DIR
+
+
+def test_bundled_world_dirs_skips_non_pack_entries(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    packs = _make_packs(tmp_path, sound=["real"], flawed={})
+    # A README placeholder and a directory with no world.json are NOT worlds.
+    (packs / "README.md").write_text("placeholder", encoding="utf-8")
+    (packs / "empty_dir").mkdir()
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", packs)
+
+    slugs = [slug for slug, _ in bundled_world_dirs()]
+    assert slugs == [VALE_SLUG, "real"]
+
+
+def test_bundled_world_dirs_handles_absent_packs_dir(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """A missing packs/ directory yields just the Vale (never raises)."""
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", tmp_path / "does_not_exist")
+    found = bundled_world_dirs()
+    assert [slug for slug, _ in found] == [VALE_SLUG]
+
+
+# ---------------------------------------------------------------------------
+# cli_worlds listing
+# ---------------------------------------------------------------------------
+
+
+def test_cli_worlds_lists_vale_sound_first(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", tmp_path / "empty")
+    out, err = StringIO(), StringIO()
+    rc = cli.cli_worlds(out=out, err=err)
+
+    assert rc == 0
+    text = out.getvalue()
+    lines = [ln for ln in text.splitlines() if ln.strip()]
+    # The very first listing line is the Vale, reported sound, with its size.
+    assert lines[0].split()[0] == VALE_SLUG
+    assert "The Vale of Understone" in lines[0]
+    assert "96x48" in lines[0]
+    assert "sound" in lines[0]
+    # The serve hint closes the listing.
+    assert "UNDERSTONE_WORLD=" in text
+    assert "the default Vale needs no setting" in text
+
+
+def test_cli_worlds_reports_sound_alternate(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    packs = _make_packs(tmp_path, sound=["mirefen"], flawed={})
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", packs)
+    out = StringIO()
+    cli.cli_worlds(out=out)
+
+    text = out.getvalue()
+    line = next(ln for ln in text.splitlines() if ln.strip().startswith("mirefen"))
+    assert "sound" in line
+    assert "flawed" not in line
+
+
+def test_cli_worlds_flags_flawed_alternate(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    # daily_turns 0 is out of its 1..100 band: the pack fails to load.
+    packs = _make_packs(tmp_path, sound=["sound_one"], flawed={"broken": {"daily_turns": 0}})
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", packs)
+    out = StringIO()
+    rc = cli.cli_worlds(out=out)
+
+    assert rc == 0  # a flawed pack is reported, never fatal
+    text = out.getvalue()
+    broken_line = next(ln for ln in text.splitlines() if ln.strip().startswith("broken"))
+    assert "flawed:" in broken_line
+    assert "daily_turns" in broken_line  # the offending field surfaces
+    # The sound pack alongside it still reports sound — one bad pack doesn't
+    # poison the survey.
+    sound_line = next(ln for ln in text.splitlines() if ln.strip().startswith("sound_one"))
+    assert "sound" in sound_line
+
+
+def test_cli_worlds_vale_sorts_before_flawed_alternate(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Even with an alphabetically-earlier flawed pack, the Vale leads."""
+    packs = _make_packs(tmp_path, sound=[], flawed={"aaa_broken": {"start_hp": 0}})
+    monkeypatch.setattr(world_pkg, "PACKS_DIR", packs)
+    out = StringIO()
+    cli.cli_worlds(out=out)
+
+    lines = [ln for ln in out.getvalue().splitlines() if ln.strip()]
+    assert lines[0].split()[0] == VALE_SLUG
+    assert lines[1].strip().startswith("aaa_broken")
+    assert "flawed:" in lines[1]
+
+
+# ---------------------------------------------------------------------------
+# the REAL bundled alternate world (no monkeypatch): The Cinder Wastes
+#
+# The tests above stub PACKS_DIR to a fixture tree so they never depend on the
+# separately-authored pack. These two exercise the actual shipped packs/ — the
+# bundled Cinder Wastes must discover, load, validate, and appear in the listing
+# as sound, so a broken or unbundled alternate trips here.
+# ---------------------------------------------------------------------------
+
+CINDER = Path(__file__).resolve().parents[1] / "understone" / "world" / "packs" / "cinder-wastes"
+
+
+def test_bundled_cinder_wastes_loads_and_validates() -> None:
+    """The bundled Cinder Wastes loads through the (strict v0.8) loader cleanly.
+
+    It is LLM-authored from AUTHORING.md alone, so this is the dogfood proof
+    that the manual + validator produce a pack the real loader accepts — and,
+    after v0.8, one that passes the stricter rare-as-guardian and single-boss
+    checks (its rares sit after their guardians; it has exactly one boss).
+    """
+    from understone.world.loader import load_world
+
+    world = load_world(CINDER)
+    assert world.name == "The Cinder Wastes"
+    assert world.settings.watch_theme == "ember"  # the thematic ember CRT palette
+    bosses = [m for m in world.monsters if m.boss]
+    assert len(bosses) == 1 and bosses[0].name == "the Magma Wyrm"
+    # The boss id resolves and is the declared endgame foe.
+    assert world.settings.boss_monster == "magma_wyrm"
+
+
+def test_cli_worlds_lists_bundled_cinder_wastes_sound() -> None:
+    """`understone worlds` discovers the real bundled Cinder Wastes as sound.
+
+    No monkeypatch: this runs against the actual packs/ directory, so it asserts
+    the genuinely-shipped second world appears in the listing (alongside the
+    fixture-based listing tests above, which stay).
+    """
+    out = StringIO()
+    rc = cli.cli_worlds(out=out)
+
+    assert rc == 0
+    line = next(ln for ln in out.getvalue().splitlines() if ln.strip().startswith("cinder-wastes"))
+    assert "The Cinder Wastes" in line
+    assert "sound" in line
+    assert "flawed" not in line

examples/door-game/tests/test_wyrm.py

@@ -0,0 +1,600 @@
+"""The Wyrm Below — the v0.2 endgame, legacy reset, and the Herald feed.
+
+Drives the challenge verb against the shipped pack: the level gate, the win
+path (Hall of Legends + reincarnation), defeat, and the stalemate flight, plus
+the run-days bookkeeping. Also pins the boss exclusion from random selection
+and proves the new level_up / defeat beats reach OTHER players' Herald.
+
+Negative-test discipline (the level gate):
+  The challenge gate is pinned by ``test_challenge_under_level_refused``. To
+  confirm the assertion has teeth, the implementer temporarily removed the
+  ``if player.level < min_level`` refusal in Game._challenge (letting an
+  under-level hero spend a turn and fight the Wyrm); the test then FAILED on
+  the unchanged-turns assertion (a turn was consumed and the refusal line was
+  absent). The guard was restored. This test is the standing regression.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from tests.conftest import (
+    fixed_clock,
+    satchel_ids,
+    set_satchel,
+    utc,
+)
+from understone.engine.models import Mode
+from understone.engine.rng import GameRNG
+from understone.game import Game
+from understone.persistence import Store
+from understone.world.loader import load_world
+
+PACK = Path(__file__).resolve().parents[1] / "understone" / "world" / "data"
+
+# Module-local aliases for the shared satchel helpers, keeping the existing
+# call sites (_set_satchel / _satchel_ids) unchanged.
+_set_satchel = set_satchel
+_satchel_ids = satchel_ids
+
+
+@pytest.fixture
+def clock() -> object:
+    return fixed_clock(utc(2026, 6, 12, 10, 0))
+
+
+def _game(tmp_path: Path, clock: object, seed: int = 7) -> Game:
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    return Game(world, store, clock=clock, rng=GameRNG(seed=seed))  # type: ignore[arg-type]
+
+
+# The flat-id-list satchel helpers (_set_satchel / _satchel_ids) live in
+# tests/conftest.py now, shared with the descend suite; they are imported above.
+
+
+def _at_dungeon(game: Game, name: str) -> object:
+    """Place an already-joined player inside the dungeon menu, at the deep floor.
+
+    The challenge verb now gates on depth as well as level: the Wyrm will not
+    stir until the hero has plumbed the deep to its floor. These challenge
+    tests exercise the win/lose/flee paths, not the gate, so the helper puts
+    the hero at the bottom (deepest_rung == the rung count). The depth gate
+    itself is exercised by the dedicated tests in test_descend.py.
+    """
+    player = game.players[name]
+    player.mode = Mode.MENU
+    player.at_location = "dungeon"
+    player.deepest_rung = len(game.world.settings.dungeon_tiers)
+    return player
+
+
+# ---------------------------------------------------------------------------
+# Boss exclusion from random selection
+# ---------------------------------------------------------------------------
+
+
+def test_boss_never_in_any_tier_band(tmp_path: Path, clock: object) -> None:
+    """The Wyrm Below is never returned by monsters_for_tier_band, any band."""
+    game = _game(tmp_path, clock)
+    world = game.world
+    tiers = [m.tier for m in world.monsters]
+    lo, hi = min(tiers), max(tiers)
+    for band_lo in range(lo, hi + 2):
+        for band_hi in range(band_lo, hi + 2):
+            band = world.monsters_for_tier_band(band_lo, band_hi)
+            assert all(not m.boss for m in band)
+            assert all(m.monster_id != "wyrm_below" for m in band)
+
+
+# ---------------------------------------------------------------------------
+# The level gate (negative-tested; see module docstring)
+# ---------------------------------------------------------------------------
+
+
+def test_challenge_under_level_refused(tmp_path: Path, clock: object) -> None:
+    """An under-level hero is turned away in-fiction, spending no turn.
+
+    See the module docstring for the revert-and-observe-failure check proving
+    the gate has teeth.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    assert player.level < game.world.settings.wyrm_min_level
+    before_turns = player.turns_left
+    before_events = len(game.events)
+
+    out = game.action("Brak", "challenge", "", "")
+
+    assert "sixth circle" in out.lower()  # names the threshold in-fiction
+    assert player.turns_left == before_turns  # no turn spent
+    assert player.level == 1  # nothing reset
+    assert len(game.events) == before_events  # no public news
+    assert player.mode is Mode.MENU  # still standing at the dungeon
+
+
+def test_challenge_at_level_threshold_is_allowed(tmp_path: Path, clock: object) -> None:
+    """Exactly at the threshold the challenge proceeds (spends a turn)."""
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level
+    player.atk, player.def_, player.hp, player.max_hp = 500, 100, 500, 500
+    before_turns = player.turns_left
+
+    out = game.action("Brak", "challenge", "", "")
+
+    assert "sixth circle" not in out.lower()  # not refused
+    assert player.turns_left == before_turns - 1  # a turn was spent
+
+
+def test_challenge_at_zero_turns_refused_clean(tmp_path: Path) -> None:
+    """At the level gate but out of turns, the challenge is refused with no effect.
+
+    A wyrm-eligible hero with an empty daily budget (and no day-roll to refill
+    it) is turned away in-fiction: no turn drops below zero, no Hall row is
+    cut, no public beat is written, wins are untouched — and the no-op player
+    row is still committed (the refusal branch upserts + commits), so a store
+    reopen sees the unchanged hero.
+    """
+    clk = _MutableClock(utc(2026, 6, 12, 10, 0))
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    game = Game(world, store, clock=clk, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level  # eligible
+    player.turns_left = 0  # but spent for the day (same day: no refill)
+    events_before = len(game.events)
+    hall_before = len(game.store.top_hall(50))
+
+    out = game.action("Brak", "challenge", "", "")
+
+    assert "tomorrow" in out.lower()  # the "too spent ... today" refusal
+    assert "sixth circle" not in out.lower()  # not the level gate
+    assert player.turns_left == 0  # never spent below zero
+    assert player.wins == 0  # no win recorded
+    assert len(game.events) == events_before  # no public feed beat
+    assert len(game.store.top_hall(50)) == hall_before  # no Hall row
+    assert player.mode is Mode.MENU  # still standing at the dungeon
+
+    # The refusal branch commits the (unchanged) row: a reopen sees the hero.
+    game.store.close()
+    reopened = Game(world, Store(tmp_path / "game.db"), clock=clk)  # type: ignore[arg-type]
+    assert reopened.players["Brak"].turns_left == 0
+    assert reopened.players["Brak"].wins == 0
+
+
+# ---------------------------------------------------------------------------
+# Win path: Hall of Legends + legacy reset
+# ---------------------------------------------------------------------------
+
+
+def test_challenge_win_resets_with_legacy(tmp_path: Path, clock: object) -> None:
+    """A win records the run, heralds it, and reincarnates the hero with a ★."""
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    # Mid-run state that must be wiped by the reset.
+    player.level, player.xp = 12, 5000
+    player.atk, player.def_, player.hp, player.max_hp = 500, 100, 500, 500
+    player.gold = 999
+    player.weapon_id, player.armor_id = "war_axe", "chainmail"
+    # State that must SURVIVE the reset.
+    player.turns_left = 4
+    player.log_cursor = 1
+    player.bestow_spent = 7
+    events_before = len(game.events)
+    settings = game.world.settings
+
+    out = game.action("Brak", "challenge", "", "")
+
+    # Win narration and the immortalised run.
+    assert "freed the vale" in out.lower()
+    assert "hall of legends" in out.lower()
+    # The legacy reset wipes xp/gold, so the Wyrm win must NOT narrate a reward
+    # the hero never keeps (the old engine appended "+400 XP, +250 gold." to the
+    # kill line, which _wyrm_won echoed verbatim). The boss's reward never lands.
+    boss = game.world.monster_by_id(game.world.settings.boss_monster)
+    assert boss is not None
+    assert f"+{boss.xp} XP" not in out  # i.e. "+400 XP"
+    assert f"+{boss.gold} gold" not in out  # i.e. "+250 gold"
+    assert "+400 XP" not in out and "+250 gold" not in out
+    hall = game.store.top_hall(5)
+    assert len(hall) == 1
+    assert hall[0].name == "Brak"
+    assert hall[0].level_at_win == 12  # the level at the moment of the kill
+    assert hall[0].run_days == 0  # same UTC day as the join under the frozen clock
+
+    # A public news beat was written (all-caps herald moment).
+    assert len(game.events) == events_before + 1
+    assert game.events[-1].kind == "wyrm_win"
+    assert "WYRM" in game.events[-1].text
+
+    # Reincarnation: stats/gold/gear/position back to first-day values.
+    assert player.wins == 1
+    assert player.level == 1
+    assert player.xp == 0
+    assert player.gold == settings.starting_gold
+    assert player.weapon_id == settings.starting_weapon
+    assert player.armor_id == settings.starting_armor
+    assert player.hp == player.max_hp
+    assert (player.x, player.y) == game.world.spawn
+    assert player.mode is Mode.TILE
+    assert player.at_location == ""
+    # The daily clock and the log cursor were deliberately left alone.
+    assert player.turns_left == 4 - 1  # only the one challenge turn was spent
+    assert player.log_cursor == 1
+    assert player.bestow_spent == 7
+
+
+def test_challenge_win_legacy_reset_spares_the_vault(tmp_path: Path, clock: object) -> None:
+    """The vault SURVIVES a Wyrm-win rebirth; carried gold resets to starting.
+
+    Banked gold is the one wealth (besides the ★) a legacy reset does not clear:
+    the strongbox is the inn's, not the reborn hero's. This deposits gold into
+    the vault through the inn, drives a Wyrm WIN, and asserts ``banked`` is
+    UNCHANGED while ``gold`` drops back to ``starting_gold``.
+
+    Negative-check (the revert-and-observe-failure discipline of this module):
+    the implementer temporarily added ``player.banked = 0`` to
+    Game._reset_with_legacy; this test then FAILED on the unchanged-``banked``
+    assertion (the vault was wiped by the rebirth). The line was restored, so
+    this test is the standing regression that the vault outlives the reset.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = game.players["Brak"]
+    # Bank some gold through the real inn path, then stand at the dungeon floor.
+    player.gold = 200
+    player.mode = Mode.MENU
+    player.at_location = "inn"
+    game.action("Brak", "deposit", "", "", amount=120)
+    assert player.banked == 120 and player.gold == 80  # vault holds; hand drained
+
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level
+    player.atk, player.def_, player.hp, player.max_hp = 500, 100, 500, 500
+
+    out = game.action("Brak", "challenge", "", "")
+
+    assert "freed the vale" in out.lower()  # a genuine win drove the reset
+    assert player.wins == 1
+    assert player.banked == 120  # the vault is untouched by the rebirth
+    assert player.gold == game.world.settings.starting_gold  # carried wealth resets
+
+
+def test_challenge_win_star_in_rank_and_hall(tmp_path: Path, clock: object) -> None:
+    """After a win, door_rank shows the ★ and renders the Hall of Legends."""
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level
+    player.atk, player.def_, player.hp, player.max_hp = 500, 100, 500, 500
+    game.action("Brak", "challenge", "", "")
+
+    out = game.rank("Brak")
+    assert "★" in out
+    assert "Hall of Legends" in out
+    assert "Brak" in out
+
+
+def test_two_wins_render_two_stars(tmp_path: Path, clock: object) -> None:
+    """A second Wyrm kill stacks a second ★ on the leaderboard name."""
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    for _ in range(2):
+        player = _at_dungeon(game, "Brak")
+        player.level = game.world.settings.wyrm_min_level
+        player.atk, player.def_, player.hp, player.max_hp = 500, 100, 500, 500
+        game.action("Brak", "challenge", "", "")
+    assert game.players["Brak"].wins == 2
+    assert "★★" in game.rank("Brak")
+
+
+# ---------------------------------------------------------------------------
+# Lose path and flight
+# ---------------------------------------------------------------------------
+
+
+def test_challenge_loss_bounces_and_heralds(tmp_path: Path, clock: object) -> None:
+    """A defeat drops the hero to 1 HP at the spawn and heralds the devouring."""
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level
+    player.atk, player.def_, player.hp, player.max_hp = 5, 1, 20, 20  # outmatched
+    events_before = len(game.events)
+
+    out = game.action("Brak", "challenge", "", "")
+
+    assert player.hp == 1
+    assert (player.x, player.y) == game.world.spawn
+    assert player.mode is Mode.TILE
+    assert player.at_location == ""
+    assert player.wins == 0  # a loss is not a win
+    assert len(game.events) == events_before + 1
+    devoured = game.events[-1]
+    assert devoured.kind == "wyrm_lose"
+    # Either phrasing of the devouring names the hero and the Wyrm.
+    assert "Brak" in devoured.text and "Wyrm" in devoured.text
+    assert "lays you low" in out.lower() or "wyrm" in out.lower()
+
+
+def _doomed_wyrm_challenger(game: Game, name: str) -> object:
+    """Stand *name* at the floor, wyrm-eligible, and doomed to a GRINDING loss.
+
+    The stats — modest atk and def, hp 50 below max_hp 80, well off the spawn —
+    make the Wyrm bout a genuine multi-round lethal loss (not a one-shot where
+    no blow lands before the save). hp 50 is none of the potion heal values
+    (15/40/70), so a death-save that sets hp to the potion's heal is unmistakable.
+    """
+    player = _at_dungeon(game, name)
+    player.level = game.world.settings.wyrm_min_level
+    player.x, player.y = 35, 25  # away from the spawn (a save never moves them)
+    player.atk, player.def_, player.hp, player.max_hp = 6, 12, 50, 80
+    return player
+
+
+def test_challenge_loss_with_potion_survives_no_legacy_reset(tmp_path: Path, clock: object) -> None:
+    """A lethal Wyrm bout with a potion is SURVIVED — no bounce, no legacy reset.
+
+    The universal death-save reaches the Wyrm: a carried draught is drunk instead
+    of the devouring. A save is NOT a win, so NOTHING resets — level, gold, and
+    ``deepest_rung`` all stand — and it is NOT the devouring either, so the hero
+    keeps their place at the dungeon. The PUBLIC beat is the survival one
+    (``wyrm_flee``, "driven back, alive but unproven"), NEVER "devoured". The
+    turn is still spent and the draught is consumed.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _doomed_wyrm_challenger(game, "Brak")
+    potion = game.world.item_by_id("greater_potion")
+    assert potion is not None
+    _set_satchel(game, player, ["greater_potion"])
+    floor = len(game.world.settings.dungeon_tiers)
+    spawn = game.world.spawn
+    before_turns = player.turns_left
+    before_level, before_gold = player.level, player.gold
+    events_before = len(game.events)
+
+    out = game.action("Brak", "challenge", "", "")
+
+    # Survived standing: hp at the potion's value, no bounce, draught spent.
+    assert player.hp == min(player.max_hp, potion.heal)
+    assert (player.x, player.y) != spawn  # NOT bounced to the spawn
+    assert player.mode is Mode.MENU  # still standing at the dungeon
+    assert _satchel_ids(game, player) == []  # the draught was spent
+    assert "death's edge" in out.lower()  # the spliced survival line
+    assert player.turns_left == before_turns - 1  # the challenge still cost a turn
+    # No win, so NO legacy reset: level, gold, and depth all stand.
+    assert player.wins == 0
+    assert player.level == before_level
+    assert player.gold == before_gold
+    assert player.deepest_rung == floor  # depth untouched (no reset to 0)
+    # The PUBLIC beat is the survival one, NOT the devouring.
+    assert len(game.events) == events_before + 1
+    beat = game.events[-1]
+    assert beat.kind == "wyrm_flee"
+    assert beat.kind != "wyrm_lose"
+    assert "fled" in beat.text.lower() or "ran" in beat.text.lower()
+
+
+def test_challenge_loss_potion_negative_without_save_devours(
+    tmp_path: Path, clock: object, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """NEGATIVE TEST: with the death-save disabled, the same potion-carrier is devoured.
+
+    The mechanical equivalent of reverting the added ``_death_save`` call in
+    ``_wyrm_lost``: we stub ``_death_save`` to always decline, then run the exact
+    scenario of the survival test. The potion-carrier must now bounce to the
+    spawn at 1 HP with the draught UNSPENT and the PUBLIC beat back to
+    ``wyrm_lose`` (devoured) — proving the death-save (not some other path) is
+    what saves them at the Wyrm. Restoring the real method (automatic when the
+    patch lifts) restores the survival behaviour.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _doomed_wyrm_challenger(game, "Brak")
+    _set_satchel(game, player, ["greater_potion"])
+    floor = len(game.world.settings.dungeon_tiers)
+    spawn = game.world.spawn
+
+    monkeypatch.setattr(Game, "_death_save", lambda self, pl, lines: False)
+    out = game.action("Brak", "challenge", "", "")
+
+    assert player.hp == 1  # devoured, not saved
+    assert (player.x, player.y) == spawn
+    assert player.mode is Mode.TILE
+    assert player.deepest_rung == floor  # a defeat keeps depth (no reset, no advance)
+    assert _satchel_ids(game, player) == ["greater_potion"]  # the draught is UNSPENT
+    assert "death's edge" not in out.lower()  # no save, no dramatic line
+    assert game.events[-1].kind == "wyrm_lose"  # the devouring beat, not the survival one
+
+
+def test_challenge_stalemate_counts_as_flight(tmp_path: Path, clock: object) -> None:
+    """A 50-round stalemate resolves as a flight: a wyrm_flee news beat.
+
+    With atk == boss def (no kill possible in the round cap) and enough HP to
+    outlast the boss's chip damage, resolve_fight returns FLED deterministically.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level
+    player.atk, player.def_, player.hp, player.max_hp = 8, 24, 200, 200
+    events_before = len(game.events)
+
+    game.action("Brak", "challenge", "", "")
+
+    assert player.wins == 0
+    assert player.hp >= 1  # never killed by a flight
+    assert len(game.events) == events_before + 1
+    assert game.events[-1].kind == "wyrm_flee"
+    assert "fled" in game.events[-1].text.lower() or "ran" in game.events[-1].text.lower()
+
+
+# ---------------------------------------------------------------------------
+# run_days from a frozen, advanced clock
+# ---------------------------------------------------------------------------
+
+
+class _MutableClock:
+    """A clock whose reported moment can be advanced between calls."""
+
+    def __init__(self, moment: object) -> None:
+        self.moment = moment
+
+    def __call__(self) -> object:
+        return self.moment
+
+
+def test_run_days_counts_whole_days(tmp_path: Path) -> None:
+    """Joining, advancing the clock three days, then winning records run_days==3."""
+    clk = _MutableClock(utc(2026, 6, 12, 10, 0))
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    game = Game(world, store, clock=clk, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+    game.join("Brak")
+    player = _at_dungeon(game, "Brak")
+    player.level = game.world.settings.wyrm_min_level
+    player.atk, player.def_, player.hp, player.max_hp = 500, 100, 500, 500
+
+    clk.moment = utc(2026, 6, 15, 12, 0)  # three days (and a couple hours) later
+    game.action("Brak", "challenge", "", "")
+
+    hall = game.store.top_hall(1)
+    assert hall[0].run_days == 3
+
+
+def test_top_hall_orders_most_recent_first(tmp_path: Path) -> None:
+    """Two heroes slay the Wyrm at advancing times; the latest tops the Hall.
+
+    Pins ``ORDER BY id DESC`` in ``Store.top_hall`` — the most recently cut
+    run is at index 0, regardless of name or level-at-win order.
+    """
+    clk = _MutableClock(utc(2026, 6, 12, 10, 0))
+    world = load_world(PACK)
+    store = Store(tmp_path / "game.db")
+    game = Game(world, store, clock=clk, rng=GameRNG(seed=7))  # type: ignore[arg-type]
+
+    def _win(name: str) -> None:
+        game.join(name)
+        hero = _at_dungeon(game, name)
+        hero.level = game.world.settings.wyrm_min_level
+        hero.atk, hero.def_, hero.hp, hero.max_hp = 500, 100, 500, 500
+        game.action(name, "challenge", "", "")
+
+    _win("Early")
+    clk.moment = utc(2026, 6, 13, 10, 0)  # a day later
+    _win("Later")
+
+    hall = game.store.top_hall(5)
+    assert len(hall) == 2
+    assert hall[0].name == "Later"  # most recent run is first
+    assert hall[1].name == "Early"
+
+
+# ---------------------------------------------------------------------------
+# Shared-feed proof: level_up and defeat reach ANOTHER player's Herald
+# ---------------------------------------------------------------------------
+
+
+def test_multi_level_jump_is_one_feed_beat_naming_final_level(
+    tmp_path: Path, clock: object
+) -> None:
+    """A single award crossing two thresholds posts ONE level_up beat, at the top.
+
+    With xp parked just under the level-3 line while still level 1, one forest
+    kill vaults the hero past both the level-2 and level-3 thresholds. The
+    public feed must carry exactly one level_up beat — a multi-level jump is one
+    notable moment, not a flood — and that beat must name the FINAL level (3),
+    not the intermediate one.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Climber")
+    climber = game.players["Climber"]
+    climber.x, climber.y = 35, 25  # forest_near zone
+    climber.atk, climber.def_, climber.hp, climber.max_hp = 100, 50, 100, 100
+    # Level 1 but xp just under L3 (300): the smallest forest reward (8) crosses
+    # both L2 (100) and L3 (300) in this one award.
+    climber.level, climber.xp = 1, 295
+    events_before = len(game.events)
+
+    game.action("Climber", "fight", "", "")
+
+    assert climber.level == 3  # vaulted two levels on the single kill
+    new_events = game.events[events_before:]
+    level_ups = [e for e in new_events if e.kind == "level_up"]
+    assert len(level_ups) == 1  # one beat, not one per level crossed
+    assert "level 3" in level_ups[0].text.lower()  # names the final level
+    assert "level 2" not in level_ups[0].text.lower()  # not the intermediate
+
+
+def test_level_up_appears_in_other_players_herald(tmp_path: Path, clock: object) -> None:
+    """A level-up by one hero is news in another hero's Herald."""
+    game = _game(tmp_path, clock)
+    game.join("Riser")
+    game.join("Watcher")
+    watcher = game.players["Watcher"]
+    watcher.log_cursor = game._latest_event_id()  # start Watcher caught up
+
+    riser = game.players["Riser"]
+    riser.x, riser.y = 35, 25  # forest_near zone
+    riser.atk, riser.def_, riser.hp, riser.max_hp = 100, 50, 100, 100
+    riser.xp = 95  # one win (>= 8 xp) crosses the level-2 threshold of 100
+    game.action("Riser", "fight", "", "")
+    assert riser.level >= 2  # the fight pushed Riser over the line
+
+    out = game.log("Watcher")
+    assert "Riser" in out
+    assert "level 2" in out.lower()
+
+
+def test_defeat_appears_in_other_players_herald(tmp_path: Path, clock: object) -> None:
+    """A defeat by a regular monster is news in another hero's Herald."""
+    game = _game(tmp_path, clock)
+    game.join("Faller")
+    game.join("Watcher")
+    watcher = game.players["Watcher"]
+    watcher.log_cursor = game._latest_event_id()
+
+    faller = game.players["Faller"]
+    faller.x, faller.y = 35, 25  # forest_near zone
+    faller.atk, faller.def_, faller.hp, faller.max_hp = 1, 0, 2, 20  # certain to fall
+    game.action("Faller", "fight", "", "")
+    assert faller.hp == 1  # bounced
+
+    out = game.log("Watcher")
+    assert "Faller" in out
+    assert "dragged back" in out.lower() or "fell to" in out.lower() or "bested" in out.lower()
+
+
+# ---------------------------------------------------------------------------
+# Movement events at the façade: no turn, no public feed
+# ---------------------------------------------------------------------------
+
+
+def test_move_events_cost_no_turn_and_write_no_feed(tmp_path: Path, clock: object) -> None:
+    """A walk that fires non-combat events spends no turn and posts no Herald news.
+
+    Walks Brak back and forth across the forest_near zone (encounter_rate 0.25)
+    enough that some non-fight event almost certainly fires; whatever happens,
+    no turn is consumed and no public event is appended.
+    """
+    game = _game(tmp_path, clock)
+    game.join("Brak")
+    player = game.players["Brak"]
+    player.x, player.y = 35, 25  # inside forest_near
+    before_turns = player.turns_left
+    before_events = len(game.events)
+
+    for _ in range(12):
+        game.move("Brak", "", "east", 1)
+        game.move("Brak", "", "west", 1)
+
+    assert player.turns_left == before_turns  # movement never costs a turn
+    assert len(game.events) == before_events  # walk texture is private

examples/door-game/understone/__init__.py

@@ -0,0 +1,3 @@
+"""Understone — a BBS-style ANSI door game served over MCP."""
+
+__version__ = "0.10.0"

examples/door-game/understone/__main__.py

@@ -0,0 +1,4 @@
+from understone.server import main
+
+if __name__ == "__main__":
+    main()

examples/door-game/understone/cli.py

@@ -0,0 +1,724 @@
+"""The pack-authoring command surface — validate a pack and scaffold a new one.
+
+This module is deliberately pure: it imports only the loader and the standard
+library, takes no part in argument parsing (``server.main`` owns the argparse
+front end), and writes to the streams it is handed. That keeps the authoring
+loop — ``newpack`` then ``validate`` — testable as plain function calls.
+
+Three entry points back the three verbs:
+
+* :func:`cli_validate` loads a pack and, on success, prints a human-readable
+  report; on failure it prints the loader's author-facing message and returns
+  a non-zero code. This is the feedback half of the loop.
+* :func:`cli_newpack` scaffolds a new pack: it copies the bundled world as a
+  starting template and writes an ``AUTHORING.md`` manual whose bands table is
+  generated from the loader's own band data, so the documented limits can
+  never drift from the enforced ones.
+* :func:`cli_worlds` lists the bundled worlds — the default Vale plus every
+  alternate pack shipped under ``world/packs/`` — loading each so it can report
+  whether it is sound or flawed, the discovery seam for "worlds without authors".
+"""
+
+from __future__ import annotations
+
+import shutil
+import sys
+from typing import TYPE_CHECKING, TextIO
+
+from understone.engine.textwidth import SAFE_PALETTE
+from understone.errors import WorldLoadError
+from understone.world import PACKAGED_WORLD_DIR, bundled_world_dirs, loader
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+    from understone.engine.world import World
+
+# The six packaged content files copied verbatim as a new pack's template.
+_PACK_FILES = (
+    "terrain.json",
+    "monsters.json",
+    "items.json",
+    "locations.json",
+    "events.json",
+    "world.json",
+)
+
+
+def cli_validate(pack_dir: Path, out: TextIO | None = None, err: TextIO | None = None) -> int:
+    """Load *pack_dir* and report; return 0 if sound, 2 if it fails to load.
+
+    On success a pack report is written to *out* and the function returns 0.
+    On any :class:`WorldLoadError` the loader's message — which names the
+    file, index, and field at fault — is written to *err* and the function
+    returns 2. The author iterates against that message until the pack loads.
+
+    *out*/*err* default to the live ``sys.stdout``/``sys.stderr`` resolved at
+    call time, so a caller (or pytest's capture) may redirect them.
+    """
+    out = out if out is not None else sys.stdout
+    err = err if err is not None else sys.stderr
+    try:
+        world = loader.load_world(pack_dir)
+    except WorldLoadError as exc:
+        print(f"The pack is flawed: {exc}", file=err)
+        return 2
+    print(_pack_report(world), file=out)
+    return 0
+
+
+def cli_newpack(dest: Path, out: TextIO | None = None, err: TextIO | None = None) -> int:
+    """Scaffold a new content pack at *dest*; return 0, or 2 if *dest* is taken.
+
+    Refuses to write into an existing non-empty directory (so an author never
+    clobbers work in progress). Otherwise it creates *dest*, copies the six
+    packaged content files as a starting template, and writes an
+    ``AUTHORING.md`` manual generated from the live loader bands. The author
+    then edits or regenerates the JSON and runs ``validate``.
+
+    *out*/*err* default to the live ``sys.stdout``/``sys.stderr`` resolved at
+    call time, so a caller (or pytest's capture) may redirect them.
+    """
+    out = out if out is not None else sys.stdout
+    err = err if err is not None else sys.stderr
+    if dest.exists() and dest.is_dir() and any(dest.iterdir()):
+        print(f"refusing to scaffold into non-empty directory: {dest}", file=err)
+        return 2
+    if dest.exists() and not dest.is_dir():
+        print(f"refusing to scaffold over a file: {dest}", file=err)
+        return 2
+
+    dest.mkdir(parents=True, exist_ok=True)
+    for name in _PACK_FILES:
+        shutil.copyfile(PACKAGED_WORLD_DIR / name, dest / name)
+    (dest / "AUTHORING.md").write_text(build_authoring_md(), encoding="utf-8")
+
+    print(f"Scaffolded a new pack at {dest}.", file=out)
+    print("Six content files plus AUTHORING.md are in place; the template is the", file=out)
+    print("shipped Vale of Understone, ready to edit or regenerate.", file=out)
+    print(f"Next: edit or regenerate the JSON, then: understone validate {dest}", file=out)
+    return 0
+
+
+def cli_worlds(out: TextIO | None = None, err: TextIO | None = None) -> int:
+    """List every bundled world, reporting each as sound or flawed; return 0.
+
+    Discovers the worlds through :func:`~understone.world.bundled_world_dirs`
+    (the default Vale first, then the alternate packs alphabetically) and loads
+    each one. Each world is one line — its slug, name, ``WxH``, and either
+    ``sound`` or ``flawed: <short reason>`` — so a shipped pack that has gone
+    out of band is visible at a glance rather than only failing at serve time.
+    A flawed world is reported, not fatal: the listing always returns 0 and
+    always ends with the hint for serving an alternate. *err* is accepted for a
+    uniform signature with the other verbs; the listing writes only to *out*.
+    """
+    out = out if out is not None else sys.stdout
+    for slug, world_dir in bundled_world_dirs():
+        print(_world_line(slug, world_dir), file=out)
+    print("", file=out)
+    print(
+        "Serve one with UNDERSTONE_WORLD=<path> (or the default Vale needs no setting).",
+        file=out,
+    )
+    return 0
+
+
+def _world_line(slug: str, world_dir: Path) -> str:
+    """Render one ``worlds`` listing line for the world at *world_dir*.
+
+    Loads the world to report its real name, dimensions, and soundness. A pack
+    that fails to load is summarised as ``flawed: <reason>`` using the loader's
+    own author-facing message (truncated to keep the listing to one line per
+    world), never raised — the listing surveys every bundled world even when one
+    is broken.
+    """
+    try:
+        world = loader.load_world(world_dir)
+    except WorldLoadError as exc:
+        return f"  {slug:<10} flawed: {_short_reason(str(exc))}"
+    return f"  {slug:<10} {world.name} — {world.width}x{world.height} — sound"
+
+
+# How much of a loader error message the one-line ``worlds`` summary keeps.
+_FLAW_REASON_MAX = 70
+
+
+def _short_reason(message: str) -> str:
+    """Trim a loader error to a single readable clause for the worlds listing."""
+    flattened = " ".join(message.split())
+    if len(flattened) <= _FLAW_REASON_MAX:
+        return flattened
+    return flattened[: _FLAW_REASON_MAX - 1].rstrip() + "…"
+
+
+def _pack_report(world: World) -> str:
+    """Render the success report for a loaded *world*.
+
+    Counts and shares are computed from the runtime world so the figures match
+    what the engine will actually run, not what the JSON nominally declares.
+    """
+    settings = world.settings
+    boss_count = sum(1 for m in world.monsters if m.boss)
+    fight_share = _fight_share_pct(world)
+
+    lines = [
+        f"{world.name} — {world.width}x{world.height}",
+        f"  monsters : {len(world.monsters)} ({boss_count} boss)",
+        f"  items    : {len(world.items)}",
+        f"  zones    : {len(world.zones)}",
+        f"  events   : {len(world.events)} ({fight_share}% fight by weight)",
+        (
+            "  settings : "
+            f"{settings.daily_turns} turns/day, "
+            f"bestow budget {settings.bestow_daily_budget}, "
+            f"Wyrm gate level {settings.wyrm_min_level}"
+        ),
+        "",
+        "This pack is sound. The door stands open.",
+    ]
+    return "\n".join(lines)
+
+
+def _fight_share_pct(world: World) -> int:
+    """Return the share of overworld encounter weight that is a ``fight``.
+
+    Reported by weight, not row count, because weight is the draw probability
+    the engine actually rolls against — it is the number an author tunes to hit
+    the ~55% fight feel.
+    """
+    total = sum(e.weight for e in world.events)
+    if total == 0:
+        return 0
+    fight = sum(e.weight for e in world.events if e.kind == "fight")
+    return round(100 * fight / total)
+
+
+def build_authoring_md() -> str:
+    """Build the AUTHORING.md manual, bands table and glyph palette included.
+
+    Both the bands section and the safe-glyph palette are generated from live
+    source — the loader's own band tables and ``textwidth.SAFE_PALETTE`` — so
+    the documented limits and the suggested glyphs are exactly what the loader
+    enforces and admits, and cannot silently drift from it.
+    """
+    md = _AUTHORING_TEMPLATE.replace("{{BANDS}}", _render_bands())
+    md = md.replace("{{PALETTE}}", _render_palette())
+    md = md.replace("{{COLOR_ROLES}}", _render_color_roles())
+    return md.replace("{{VALIDATE_COVERAGE}}", _render_validate_coverage())
+
+
+def _render_bands() -> str:
+    """Render the bands reference straight from the loader's band data."""
+    parts: list[str] = []
+
+    parts.append("### Map and counts\n")
+    parts.append(
+        f"* Map width and height: each `{loader.MAP_DIM_MIN}`..`{loader.MAP_DIM_MAX}` cells."
+    )
+    # monsters/items/events are their own files; locations and zones are lists
+    # inside world.json, so name each cap's real source.
+    count_source = {
+        "monsters": "`monsters.json`",
+        "items": "`items.json`",
+        "events": "`events.json`",
+        "locations": "`world.json` → `locations`",
+        "zones": "`world.json` → `zones`",
+    }
+    for name, cap in loader.MAX_COUNTS.items():
+        parts.append(f"* {count_source[name]}: at most `{cap}` entries.")
+    parts.append(
+        f"* Display names (monster, item, location): at most "
+        f"`{loader.MAX_NAME_LEN}` printable characters."
+    )
+    parts.append(
+        "* Map glyphs (terrain, location, legend keys): exactly one terminal "
+        "column (one printable code point, no fullwidth runes, no combining "
+        "marks — see the width rule above), and never one of "
+        + ", ".join(f"`{g}`" for g in _reserved_glyph_list())
+        + " (the frame box-drawing lines and the `@`/`☻` player markers)."
+    )
+    parts.append("")
+
+    parts.append("### Economy and progression settings (`world.json` → `settings`)\n")
+    parts.append("| field | allowed range |")
+    parts.append("| --- | --- |")
+    for field_name, (lo, hi) in loader.SETTINGS_BANDS.items():
+        rng = f"{lo}..{hi}" if hi is not None else f"{lo} or more"
+        parts.append(f"| `{field_name}` | `{rng}` |")
+    parts.append("")
+
+    parts.append("### Overworld event amounts (`events.json`, per kind)\n")
+    parts.append("| kind | min..max amount |")
+    parts.append("| --- | --- |")
+    for kind, (lo, hi) in loader.EVENT_AMOUNT_BANDS.items():
+        parts.append(f"| `{kind}` | `{lo}..{hi}` |")
+    parts.append(
+        "\n(`fight` and `lore` carry no amount; `fight` draws its foe from the "
+        "zone tier band, `lore` is pure flavour text.)\n"
+    )
+
+    parts.append("### Watch theme (`world.json` → `settings.watch_theme`)\n")
+    legal = ", ".join(f"`{name}`" for name in sorted(loader.WATCH_THEMES))
+    parts.append(
+        f"OPTIONAL. The CRT palette the live Watch page paints your world in, "
+        f"one of: {legal}. It defaults to `{loader.DEFAULT_WATCH_THEME}` (the "
+        f"original green phosphor), so you may leave it out entirely — a pack "
+        f"that omits it looks exactly as the bundled Vale always has. Set it to "
+        f"give your world its own colour: `amber` is a warm gold monitor, `ice` "
+        f"a cold pale blue, `ember` a hot red/orange. An unknown name is a load "
+        f"error naming the legal set."
+    )
+
+    parts.append("\n### The ore-gated forge (`world.json` → `settings`)\n")
+    ore_per = loader.SETTINGS_BANDS["forge_ore_per_plus"]
+    dungeon = loader.SETTINGS_BANDS["ore_dungeon_drop"]
+    parts.append(
+        "Forging a +1 edge now costs both GOLD and ORE — a `material` item the "
+        "hero earns in combat, never buys. Four settings bind it:"
+    )
+    parts.append(
+        "* `forge_ore_item` — REQUIRED. The item id of your world's forge ore; "
+        "it must name an `items.json` entry whose `slot` is `material` (an "
+        "unknown id or a non-material slot is a load error). The Vale uses "
+        "`iron_ore`."
+    )
+    parts.append(
+        f"* `forge_ore_per_plus` — band `{ore_per[0]}..{ore_per[1]}`. Ore per +1 "
+        f"step: a +N forge costs `(current_plus + 1) * forge_ore_per_plus` ore. "
+        f"{_forge_ore_worked_example()}"
+    )
+    parts.append(
+        f"* `ore_dungeon_drop` — band `{dungeon[0]}..{dungeon[1]}`. Ore granted "
+        f"on every WON dungeon rung — the reliable source. The Vale drops 2."
+    )
+    parts.append(
+        "* `ore_forest_chance` — a `0.0`..`1.0` probability (a float, validated "
+        "outside the integer band table). The chance a WON forest fight yields "
+        "one ore — the occasional bonus source. The Vale uses `0.2`."
+    )
+    parts.append(
+        "\nOre rides the satchel as a stack, so it shares the `satchel_max` "
+        "DISTINCT-stack budget with potions (per-stack quantity is unbounded). "
+        "Tune the two sources so a hero who descends steadily earns enough ore "
+        "to forge without grinding — the `simulate` bot will tell you if the "
+        "gate stalls a winnable run."
+    )
+
+    return "\n".join(parts)
+
+
+def _forge_ore_worked_example() -> str:
+    """Render the per-step ore costs from the bundled Vale's live forge settings.
+
+    The starter template :func:`cli_newpack` copies IS the bundled Vale, so the
+    worked figures are computed from its actual ``forge_ore_per_plus`` and
+    ``forge_max_plus`` rather than hardcoded — a retune of the template moves
+    the manual with it. The steps are ``per_plus * (i + 1)`` for each ``i`` in
+    ``range(forge_max_plus)``; the total is what it costs to max one slot.
+    """
+    settings = loader.load_world(PACKAGED_WORLD_DIR).settings
+    per_plus = settings.forge_ore_per_plus
+    max_plus = settings.forge_max_plus
+    steps = [per_plus * (i + 1) for i in range(max_plus)]
+    if not steps:
+        return (
+            f"At the template's value of {per_plus}, slots cannot be forged (`forge_max_plus` 0)."
+        )
+    ladder = ", ".join(str(cost) for cost in steps)
+    total = sum(steps)
+    return (
+        f"At the template's value of {per_plus}, the steps cost {ladder} ore "
+        f"({total} ore to max a slot at `forge_max_plus` {max_plus})."
+    )
+
+
+def _reserved_glyph_list() -> list[str]:
+    """Return the reserved glyphs in a stable, readable order for the manual."""
+    box = [g for g in "┌┐└┘─│═" if g in loader.RESERVED_GLYPHS]
+    actors = [g for g in "@☻" if g in loader.RESERVED_GLYPHS]
+    return box + actors
+
+
+def _render_palette() -> str:
+    """Render the safe-glyph appendix straight from ``textwidth.SAFE_PALETTE``.
+
+    The glyphs are emitted in their declared order, wrapped in backticks so the
+    monospace renders them as discrete cells. Generated from the live constant,
+    so the suggested palette is exactly the set the loader's width gate admits.
+    """
+    glyphs = " ".join(f"`{g}`" for g in SAFE_PALETTE)
+    return (
+        "Any single-column glyph the loader accepts is fair game, but these "
+        "carry the period BBS / CP437 flavour and are all guaranteed safe:\n\n"
+        f"{glyphs}"
+    )
+
+
+def _render_color_roles() -> str:
+    """Render the author-assignable colour roles, generated from the Color enum.
+
+    The Watch knows how to paint exactly the roles in ``screen.palette.Color``;
+    ``Color.assignable()`` is the single source for which of those an author may
+    put on terrain or a location (the runtime overlay roles an actor/item wears,
+    and the DEFAULT fallback, are filtered out there). Generated from the enum,
+    so the documented vocabulary can never drift from what the Watch can
+    actually colour — the same can't-drift discipline as the bands and the
+    safe-glyph palette. ``color`` itself stays advisory: the loader does not
+    validate it, so a typo is harmless and an unknown role just paints as the
+    default; these are simply the roles the Watch recognises.
+    """
+    from understone.screen.palette import Color
+
+    return ", ".join(f"`{role.value}`" for role in Color.assignable())
+
+
+def _render_validate_coverage() -> str:
+    """Render the list of rules the loader actually enforces, generated from it.
+
+    The figures that can drift (the number of banded settings, the name-length
+    cap, the reserved glyphs) are read from the live loader so the list cannot
+    fall out of step with what `validate` does; the prose names each family of
+    check. This is the machine-enforced half of the honesty split in the manual
+    — the eyeball-only half is hand-written below it, because "is the fiction
+    any good" is exactly what the loader can never see.
+    """
+    settings_count = len(loader.SETTINGS_BANDS)
+    reserved = ", ".join(f"`{g}`" for g in _reserved_glyph_list())
+    bullets = [
+        f"* **Economy and progression bands** — every one of the {settings_count} `settings` fields must sit in its allowed range (the table above), and `growth` must be present and non-negative.",
+        f"* **Glyph safety** — every terrain, location, and legend glyph must render exactly one column and must not be a reserved marker ({reserved}).",
+        "* **Map integrity** — `width`/`height` in band, every `terrain_rows` row exactly `width` long with `height` rows, and every row character in the `legend`.",
+        "* **Walkability** — `spawn` and every placed location must sit on walkable terrain (and no two locations share a cell).",
+        f"* **Display-name length** — every monster, item, and location name within `{loader.MAX_NAME_LEN}` printable characters; content lists within their caps.",
+        "* **The fight row** — `events.json` must hold at least one `fight` entry, with weights `> 0`, `min <= max`, and amounts in their per-kind band.",
+        '* **Cross-references** — `legend` → terrain key, location placements → `locations.json` keys, `starting_weapon`/`starting_armor` → item ids, `boss_monster` → a monster flagged `"boss": true`, `rare_drop_item` → a consumable item id, and `forge_ore_item` → a `material` item id.',
+        "* **Zone tiers** — every zone's tier band must overlap at least one monster tier.",
+        "* **Dungeon ladder** — every `dungeon_tiers` tier must have a non-boss monster, and that tier's FIRST monster (its fixed rung guardian) must not be `rare`.",
+        '* **Exactly one boss** — at most one monster may carry `"boss": true`.',
+    ]
+    return "\n".join(bullets)
+
+
+_AUTHORING_TEMPLATE = """\
+# Authoring a world pack for Understone
+
+A *world pack* is a directory of six JSON files that the server loads at start
+to become the entire game world — its map, its monsters, its economy, its
+endgame. There is no code to write: you describe a world as data, the loader
+validates it hard, and the server runs it. This file is the manual; you can
+follow it cold, by hand or with an LLM.
+
+The loop is short:
+
+1. `understone newpack mypack` — scaffold this template (you are reading the
+   copy it wrote into `mypack/AUTHORING.md`).
+2. Edit or regenerate the JSON files to describe your world.
+3. `understone validate mypack` — the loader checks the pack and either prints
+   a report ending **"This pack is sound. The door stands open."** or tells you
+   exactly which file, row, and field is wrong.
+4. Repeat step 2 until it is sound, then serve it:
+   `UNDERSTONE_WORLD=mypack understone`.
+
+The loader's error messages are written FOR you: every failure names the file,
+the index, and the field, and says what was expected. Treat them as the
+feedback loop — iterate until the report says the door stands open.
+
+---
+
+## The six files and how they fit together
+
+| file | shape | holds |
+| --- | --- | --- |
+| `terrain.json` | object keyed by legend char | terrain kinds: glyph, walkability, encounter rate |
+| `monsters.json` | list | monster stat blocks, tiered; one flagged the boss |
+| `items.json` | list | weapons, armour, consumables for the shop |
+| `locations.json` | object keyed by location key | building kinds: name, glyph, menu actions, flavour |
+| `events.json` | object with an `events` list | the weighted overworld encounter table |
+| `world.json` | object | the map, placements, zones, and `settings` that bind it all |
+
+The cross-references the loader enforces:
+
+* every character in `world.json` → `legend` must name a terrain `key` from
+  `terrain.json`; every character in `terrain_rows` must be in that legend;
+* every placement in `world.json` → `locations` must name a key defined in
+  `locations.json`, and must sit on walkable terrain;
+* `settings.starting_weapon` / `starting_armor` must be ids from
+  `items.json`; `settings.boss_monster` must be an id from `monsters.json`
+  that is flagged `"boss": true`; `settings.rare_drop_item` must be an id from
+  `items.json` whose `slot` is `consumable`; `settings.forge_ore_item` must be
+  an id from `items.json` whose `slot` is `material`;
+* every tier in `settings.dungeon_tiers` must be backed by a NON-boss monster;
+* every zone's tier band must overlap at least one monster tier.
+
+---
+
+## File-by-file schema
+
+### `terrain.json`
+
+An object whose keys are the single-character legend symbols used in the map.
+
+```json
+{
+  ".": {"key": "grass", "glyph": ".", "walkable": true, "encounter_rate": 0.1, "color": "floor"}
+}
+```
+
+* `key` — internal name the map legend resolves to.
+* `glyph` — the single character drawn on the map (see glyph rules below).
+* `walkable` — may a player stand here.
+* `encounter_rate` — `0.0`..`1.0`, the per-step chance a walk rolls the event
+  table on this terrain.
+* `color` — a palette role string. It is **advisory and not validated**: the
+  loader stores it but the text frame draws glyphs only (it is monochrome), so
+  any string loads and an unrecognised role simply maps to the default at render
+  time. Where colour DOES show is the live Watch page, which paints each role a
+  distinct hue. The roles the Watch knows how to paint — pick the closest fit —
+  are: {{COLOR_ROLES}}. A typo here is harmless, not a load error; it just
+  paints as the default. The four runtime overlay colours (the hero, rival
+  players, monsters, dropped items) are set by the engine, not assignable here.
+
+### `monsters.json`
+
+A list of stat blocks. `tier` groups foes by difficulty; zones and the dungeon
+gauntlet draw from tiers. Exactly one monster should be the boss.
+
+```json
+{"tier": 2, "name": "Goblin", "hp": 12, "atk": 5, "def": 1, "xp": 18, "gold": 7}
+```
+
+The boss adds an `id` and `"boss": true`, and is referenced by
+`settings.boss_monster`:
+
+```json
+{"tier": 6, "name": "the Wyrm Below", "hp": 120, "atk": 24, "def": 8,
+ "xp": 400, "gold": 250, "boss": true, "id": "wyrm_below"}
+```
+
+Two optional fields tune random forest encounters. `weight` (default `10`,
+must be `> 0`) biases the weighted draw within a zone band — a low weight
+surfaces seldom — and `rare` (default `false`) marks a named beast that, on
+its kill, fires a public Herald flash and drops the pack's `rare_drop_item`
+into the slayer's satchel. Rung guardians ignore both (a rung always takes the
+FIRST monster of its tier, never a weighted roll), so a rare should not be the
+first entry of a tier that backs a `dungeon_tiers` rung.
+
+```json
+{"tier": 2, "name": "the Gilded Stag", "hp": 16, "atk": 6, "def": 2,
+ "xp": 40, "gold": 60, "weight": 1, "rare": true}
+```
+
+### `items.json`
+
+A list of equipment, consumables, and crafting materials. `slot` is `weapon`,
+`armor`, `consumable`, or `material`. Weapons add `atk`, armour adds `def`,
+consumables `heal`; a `material` carries none of these — it is the forge ORE,
+carried in the satchel and spent at the forge.
+
+```json
+{"id": "short_sword", "name": "Short Sword", "slot": "weapon", "atk": 5, "price": 40}
+```
+
+The forge ore is a `material` item the player EARNS in combat (not the shop):
+price it `0` — ore is never bought or sold — and point `settings.forge_ore_item`
+at its id. A won dungeon rung always drops `settings.ore_dungeon_drop` of it, and
+a won forest fight has a `settings.ore_forest_chance` chance of one.
+
+```json
+{"id": "iron_ore", "name": "Iron Ore", "slot": "material", "price": 0}
+```
+
+### `locations.json`
+
+An object keyed by location key. Each entry is a building kind with a menu of
+`actions` the player may take inside it.
+
+```json
+{
+  "inn": {"kind": "inn", "name": "The Sleeping Drake", "glyph": "I",
+          "color": "town", "actions": ["rest", "gamble", "leave"],
+          "flavor": ["Lamplight pools on worn oak tables."]}
+}
+```
+
+Give each building the menu that matches its role. The four building kinds and
+the verbs the engine honours inside each are:
+
+| `kind` | actions the engine understands |
+| --- | --- |
+| `inn` | `rest`, `deposit`, `withdraw`, `gamble`, `leave` |
+| `shop` | `buy`, `sell`, `forge`, `leave` |
+| `healer` | `heal`, `leave` |
+| `dungeon` | `descend`, `challenge`, `leave` |
+
+The inn's `deposit`/`withdraw` are the VAULT: a player banks gold into the inn
+strongbox (`deposit amount=<gold>`) and draws it back (`withdraw amount=<gold>`).
+Banked gold is SAFE from ambush — a sleeping-robber only ever lifts gold in hand
+— and it SURVIVES the Wyrm-win legacy reset, so it is the one store of wealth
+that carries across runs. Both cost no turn.
+
+`quaff` (drink a satchel tonic) is legal **anywhere** and needs no menu entry.
+The `actions` list is advisory — it is the menu the narrator offers, NOT a
+validated whitelist (see "What `validate` checks" below): a verb the engine does
+not back simply confuses the narrator, so give each building only the verbs from
+its row above.
+
+### `events.json`
+
+An object with an `events` list — the weighted overworld encounter table the
+server rolls as a player walks.
+
+```json
+{"events": [
+  {"kind": "fight", "weight": 82, "text": "Something snarls out of the brush."},
+  {"kind": "gold", "weight": 8, "text": "a rotted coin-purse", "min": 4, "max": 12}
+]}
+```
+
+* `kind` — `fight`, `gold`, `heal`, `trap`, or `lore`.
+* `weight` — relative draw weight (`> 0`).
+* `text` — required (non-empty) for every kind except `fight`.
+* `min`/`max` — required for the value-bearing kinds (`gold`, `heal`, `trap`).
+
+There MUST be at least one `fight` row, or a walk could never find a monster.
+
+### `world.json`
+
+The binding file: `name`, `width`, `height`, `spawn` `[x, y]` (the hero's start
+cell, which must be on walkable terrain), a `legend` mapping characters to
+terrain keys, `terrain_rows` (one string per row, each exactly `width` long), a
+`locations` list of `{"key", "x", "y"}` placements (each also on walkable
+terrain), a `zones` list (rectangles that bias monster tiers), and a `settings`
+object.
+
+```json
+{"key": "forest_near", "rect": [30, 18, 60, 36], "tier_lo": 1, "tier_hi": 2}
+```
+
+---
+
+## The bands — the limits the loader enforces
+
+These are generated from the loader's own tables, so they are exactly what
+`validate` checks. A value outside its band is a load error.
+
+{{BANDS}}
+
+---
+
+## Glyph width — the one-column rule
+
+Every glyph drawn on the map must occupy **exactly one terminal column**. The
+frames are box-drawing rectangles; a glyph that renders two columns (a CJK
+ideograph like `龍`, an emoji like `🌲`, a fullwidth `Ａ`) shoves its row right
+and tears the border, and a combining mark (a decomposed `é`, a lone accent)
+stacks onto its neighbour and breaks the count the other way. The loader
+rejects all of these at load.
+
+What is admitted is judged for the **Western monospace** metrics every
+Understone surface actually uses (the Watch's pinned font stack, a chat
+client's code block): under those metrics the East-Asian "Ambiguous" width
+class renders single-column, and that class is the CP437 heartland — `█`, `♣`,
+`↑`, `∩`, `≈`, `★` all live there — so the rule admits it and bars only the
+genuinely double-width Wide and Fullwidth classes.
+
+### Safe glyph palette
+
+{{PALETTE}}
+
+---
+
+## Design guidance
+
+**Turn economy.** `daily_turns` is the whole pacing lever: only fighting,
+descending, and challenging the Wyrm spend a turn (moving, resting, shopping
+are free). A small budget (the Vale uses 10) makes this a correspondence game
+played a little each day. Set `rest_cost`, `heal_cost_per_hp`, and shop prices
+so a day's gold roughly covers a day's recovery — too cheap and there is no
+tension, too dear and a hero stalls.
+
+**Tier curve.** Lay monster tiers as a rising staircase: each tier should be a
+real step up in `hp`/`atk` and a real step up in `xp`/`gold`, so the reward of
+pushing into a harder zone pays for the risk. Keep two or three foes per tier
+for variety. The boss should tower over the top random tier — it is the climax.
+
+**Encounter feel.** Aim for roughly 55% of overworld encounter WEIGHT on
+`fight` rows; the rest is the texture of travel — small gold finds, healing
+springs, harmless traps, and lore that hints at the endgame. (The validate
+report prints your actual fight share so you can tune it.)
+
+**Glyphs.** Map glyphs must render as exactly one terminal column (see the
+one-column rule above) and must never collide with the frame's box-drawing
+lines or the `@`/`☻` player markers. Pick glyphs that read at a glance — the
+bundled Vale uses `.` open ground, `≋` water, `♣` tree, `⌂` inn, `$` shop, `✚`
+healer, `∩` dungeon — and lean on the safe palette for period flavour.
+
+**Boss rules.** Exactly one monster carries `"boss": true` and an `id`, and
+`settings.boss_monster` points at it. The boss is the only win condition and is
+faced only through the `challenge` verb, gated by `settings.wyrm_min_level`. A
+boss tier must NOT appear in `settings.dungeon_tiers`: the gauntlet excludes
+boss monsters, so a boss-only rung would be unfillable — back every dungeon
+tier with at least one ordinary monster.
+
+**The deep, the satchel, and the forge.** `dungeon_tiers` is now a RUNG LADDER
+fought one rung per `descend` — list the tiers shallow-to-deep, and make it long
+enough to feel like a journey (the Vale uses three). The Wyrm gates on reaching
+the floor as well as on level. Size the satchel with `satchel_max` — it caps the
+DISTINCT stacks the bag holds (potions and ore each take a slot; per-stack
+quantity is unbounded), and it is the death-save reserve, so keep it small (the
+Vale carries 3). The forge is the late-game GOLD-AND-ORE sink: `forge_base_cost`
+is the gold price of a +1 edge and scales up each tier (`base * (current_plus +
+1)`), capped at `forge_max_plus`, and each step ALSO costs ore (see the ore-gated
+forge above). Ore is won in the deep (and seldom in the forest), so the forge is
+fed by descending — price the gold so a fully-forged piece is a multi-day saving,
+and set the ore sources so a steady delver can afford it without a grind.
+
+**Rare beasts.** A rare monster is a small legend: give it a low `weight` so it
+surfaces seldom, stats and rewards a clear notch above its tier, and remember it
+always drops `rare_drop_item` (a consumable) into the satchel. Keep rares OFF
+the first slot of any `dungeon_tiers` tier, or they would become a fixed rung
+guardian instead of a rare roll — `validate` now ENFORCES this, so a rare in a
+dungeon tier's lead slot is a load error, not just bad form. Place the rare
+anywhere after that tier's first ordinary monster.
+
+**Location menus.** Give each building only the actions it can honour, drawn
+from the per-kind table under `locations.json` above. An inn that offers `buy`
+but no shop logic will confuse the narrator. This is the one major thing
+`validate` does NOT check (see below): a wrong or invented verb loads fine and
+only muddles the narration, so it is on you to match each menu to its building.
+
+---
+
+## The validate loop
+
+Run `understone validate mypack` after every change. On success you get a
+report — name, size, monster/item/zone/event counts, fight share, and the key
+settings — ending in **"This pack is sound. The door stands open."** On
+failure you get one precise line naming the file, the row, and the field.
+
+The error messages are deliberately instructive: they are the authoring API.
+Keep editing and re-validating until the door stands open, then point the
+server at your pack with `UNDERSTONE_WORLD=mypack`.
+
+### What `validate` checks, and what it cannot
+
+`validate` runs your pack through the very loader the server uses, so a pack
+that validates will load and serve. But the loader checks *structure and
+references*, not *meaning* — it cannot read your fiction. Keep the split honest:
+
+**`validate` DOES catch (a load error if wrong):**
+
+{{VALIDATE_COVERAGE}}
+
+**`validate` does NOT catch (the eyeball-only short list):**
+
+* **Location menu `actions` contents.** The list is the narrator's menu, not a
+  validated whitelist: a verb the engine does not back (a typo, or a fictional
+  `pray`) loads fine and only confuses the narration. Match each building's menu
+  to the per-kind table under `locations.json`.
+* **Flavour and narration quality.** Names, `flavor` lines, event `text`, the
+  feel of the tier curve and the economy — the loader checks they are present
+  and in band, never whether they are *good*. That judgement is yours; the
+  `simulate` bot can tell you a world is winnable and sanely paced, but only you
+  can tell whether it is worth playing.
+"""

examples/door-game/understone/engine/__init__.py

@@ -0,0 +1,6 @@
+"""Game engine — pure stdlib mechanics with injectable clock and RNG.
+
+This package has no knowledge of MCP, persistence, or rendering. Every
+function takes its inputs explicitly (world, player, rng, clock) so the
+mechanics are deterministic under test.
+"""

examples/door-game/understone/engine/combat.py

@@ -0,0 +1,117 @@
+"""Combat resolution — pure math over an injected RNG.
+
+A fight runs deterministic rounds: both sides trade blows until one drops.
+Damage is ``max(1, attacker_atk - defender_def)`` jittered by a small RNG
+swing so identical stats still produce varied logs. The result is a value
+object; turn accounting and the spawn-bounce on defeat are applied by the
+caller (the game façade), keeping this module side-effect free.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from enum import StrEnum
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from understone.engine.models import Monster, Player
+    from understone.engine.rng import GameRNG
+
+_MAX_ROUNDS = 50
+
+
+class Outcome(StrEnum):
+    """How a fight ended."""
+
+    WIN = "win"
+    LOSE = "lose"
+    FLED = "fled"
+
+
+@dataclass(slots=True)
+class FightResult:
+    """The full outcome of a combat exchange.
+
+    Deltas are signed and meant to be applied to the player by the caller.
+    ``bounce_to_spawn`` signals a defeat: the caller sets ``hp`` to 1 and
+    moves the player back to the spawn point.
+    """
+
+    outcome: Outcome
+    log: list[str] = field(default_factory=list)
+    xp_delta: int = 0
+    gold_delta: int = 0
+    hp_delta: int = 0
+    bounce_to_spawn: bool = False
+    monster_name: str = ""
+
+
+def _swing(rng: GameRNG, atk: int, def_: int) -> int:
+    """Return one blow's damage: floor of 1, with a small RNG jitter."""
+    base = atk - def_
+    jitter = rng.randint(-1, 2)
+    return max(1, base + jitter)
+
+
+def resolve_fight(rng: GameRNG, player: Player, monster: Monster) -> FightResult:
+    """Run a full fight between *player* and *monster*.
+
+    The player strikes first each round. On victory the player banks the
+    monster's xp/gold and keeps any hp lost during the exchange. On defeat
+    the result flags a spawn bounce for the caller to apply.
+    """
+    result = FightResult(outcome=Outcome.WIN, monster_name=monster.name)
+    player_hp = player.hp
+    monster_hp = monster.hp
+    result.log.append(f"You close with the {monster.name}.")
+
+    for _ in range(_MAX_ROUNDS):
+        dealt = _swing(rng, player.atk, monster.def_)
+        monster_hp -= dealt
+        result.log.append(f"You strike for {dealt}. ({monster.name}: {max(monster_hp, 0)} HP)")
+        if monster_hp <= 0:
+            result.outcome = Outcome.WIN
+            result.xp_delta = monster.xp
+            result.gold_delta = monster.gold
+            result.hp_delta = player_hp - player.hp
+            # The kill round (the strike line above) stays; the "falls + reward"
+            # sentence is composed by the caller at the moment it actually banks
+            # the xp/gold, so a reward is never narrated where none is applied
+            # (e.g. the Wyrm-win legacy reset, which keeps no xp/gold).
+            return result
+
+        taken = _swing(rng, monster.atk, player.def_)
+        player_hp -= taken
+        result.log.append(f"It hits back for {taken}. (You: {max(player_hp, 0)} HP)")
+        if player_hp <= 0:
+            result.outcome = Outcome.LOSE
+            result.bounce_to_spawn = True
+            result.log.append(
+                f"The {monster.name} lays you low. You wake at the spawn, barely alive."
+            )
+            return result
+
+    # Stalemate guard: treat an unresolved marathon as a flight to safety.
+    result.outcome = Outcome.FLED
+    result.hp_delta = player_hp - player.hp
+    result.log.append("The fight grinds on until you break away, winded.")
+    return result
+
+
+def resolve_flee(rng: GameRNG, player: Player, monster: Monster) -> FightResult:
+    """Attempt to flee a fight.
+
+    A successful flee escapes clean. A failed flee costs one free blow from
+    the monster but never drops the player below 1 HP (fleeing is a way out,
+    not a death trap).
+    """
+    result = FightResult(outcome=Outcome.FLED, monster_name=monster.name)
+    if rng.chance(0.6):
+        result.log.append(f"You slip away from the {monster.name}.")
+        return result
+
+    taken = _swing(rng, monster.atk, player.def_)
+    taken = min(taken, max(player.hp - 1, 0))
+    result.hp_delta = -taken
+    result.log.append(f"You turn to run; the {monster.name} catches you for {taken} as you go.")
+    return result

examples/door-game/understone/engine/leveling.py

@@ -0,0 +1,108 @@
+"""Experience, level-ups, and the inn/healer restorative maths.
+
+The XP curve and stat growth come from the content pack's settings, so no
+progression constants live in this module. Level-ups loop (a single XP
+award can cross several thresholds), grant flat stat growth, and fully
+heal on each level gained.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from understone.engine.models import Player, Settings
+
+
+@dataclass(slots=True)
+class LevelUp:
+    """A record of a single level gained, for narration."""
+
+    new_level: int
+    hp_gain: int
+    atk_gain: int
+    def_gain: int
+
+
+def xp_for_level(level: int, settings: Settings) -> int:
+    """Return cumulative XP required to *reach* ``level``.
+
+    Level 1 needs 0. The default curve is ``base * n*(n+1)/2`` over the
+    completed levels, i.e. a triangular ramp scaled by ``xp_base``.
+    """
+    if level <= 1:
+        return 0
+    completed = level - 1
+    return settings.xp_base * completed * (completed + 1) // 2
+
+
+def apply_xp(player: Player, amount: int, settings: Settings) -> list[LevelUp]:
+    """Award ``amount`` XP to *player*, applying every level-up it unlocks.
+
+    Returns one :class:`LevelUp` per level gained (empty when none). Each
+    level grants flat growth from settings and fully heals the player.
+    """
+    player.xp += max(0, amount)
+    gains: list[LevelUp] = []
+    while player.xp >= xp_for_level(player.level + 1, settings):
+        player.level += 1
+        player.max_hp += settings.growth_max_hp
+        player.atk += settings.growth_atk
+        player.def_ += settings.growth_def
+        player.hp = player.max_hp
+        gains.append(
+            LevelUp(
+                new_level=player.level,
+                hp_gain=settings.growth_max_hp,
+                atk_gain=settings.growth_atk,
+                def_gain=settings.growth_def,
+            )
+        )
+    return gains
+
+
+def rest(player: Player, cost: int) -> bool:
+    """Fully heal *player* at the inn for a flat ``cost``.
+
+    Returns ``False`` without mutation when the player cannot afford it.
+    Resting when already at full HP still succeeds (and still charges),
+    matching the inn's flat-rate fiction.
+    """
+    if player.gold < cost:
+        return False
+    player.gold -= cost
+    player.hp = player.max_hp
+    return True
+
+
+@dataclass(slots=True)
+class HealResult:
+    """Outcome of a healer purchase: HP actually restored and gold spent."""
+
+    healed: int
+    cost: int
+
+
+def heal(player: Player, amount: int, cost_per_hp: int) -> HealResult:
+    """Restore up to ``amount`` HP at ``cost_per_hp`` gold each.
+
+    Heals only the missing portion, charges only for HP actually restored,
+    and is further bounded by what the player can afford. Returns the amount
+    healed and the gold spent (both zero when nothing could be done).
+    """
+    missing = player.max_hp - player.hp
+    want = max(0, min(amount, missing))
+    if want <= 0 or cost_per_hp < 0:
+        return HealResult(healed=0, cost=0)
+    if cost_per_hp == 0:
+        player.hp += want
+        return HealResult(healed=want, cost=0)
+    affordable = player.gold // cost_per_hp
+    apply = min(want, affordable)
+    if apply <= 0:
+        return HealResult(healed=0, cost=0)
+    spent = apply * cost_per_hp
+    player.hp += apply
+    player.gold -= spent
+    return HealResult(healed=apply, cost=spent)

examples/door-game/understone/engine/log.py

@@ -0,0 +1,63 @@
+"""The shared event log — a world-wide feed players catch up on.
+
+Events are append-only and ordered by insertion. Each player tracks a
+cursor (the id of the last event they have seen); ``since`` returns the
+slice after a cursor and the new cursor to persist.
+
+An event carries a ``target``: empty means PUBLIC (the broadsheet and the
+lobby TV), a player name means a PRIVATE note that only that player reads in
+their own catch-up. Targeted rows ride the same id order as public ones, so
+the cursor advances identically whether or not a private note was shown.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True, slots=True)
+class Event:
+    """A single logged happening in the shared world.
+
+    ``target`` is the empty string for public events (heralded to everyone)
+    or a player's name for a private note delivered only to that player.
+    """
+
+    event_id: int
+    ts: str
+    kind: str
+    actor: str
+    text: str
+    target: str = ""
+
+
+def since(events: list[Event], cursor: int) -> tuple[list[Event], int]:
+    """Return events newer than ``cursor`` and the cursor to store next.
+
+    Events are kept in ascending id order (the store hydrates the newest tail
+    and reverses it to ascending; appends are monotonic), so the last fresh
+    event carries the highest id; that becomes the new cursor.
+    When nothing is new the input cursor is returned, so advancing is
+    idempotent.
+    """
+    fresh = [e for e in events if e.event_id > cursor]
+    if not fresh:
+        return [], cursor
+    return fresh, fresh[-1].event_id
+
+
+def since_visible(events: list[Event], cursor: int, viewer: str) -> tuple[list[Event], int]:
+    """Like :func:`since`, but hide private notes not addressed to *viewer*.
+
+    Returns the events newer than ``cursor`` that *viewer* may read — every
+    public event (empty ``target``) plus the private notes addressed to them —
+    and the new cursor. The cursor advances to the highest id PAST the old
+    cursor regardless of visibility, so a private note for someone else is
+    consumed (never re-scanned) without ever being shown here.
+    """
+    fresh = [e for e in events if e.event_id > cursor]
+    if not fresh:
+        return [], cursor
+    new_cursor = fresh[-1].event_id
+    visible = [e for e in fresh if not e.target or e.target == viewer]
+    return visible, new_cursor

examples/door-game/understone/engine/models.py

@@ -0,0 +1,232 @@
+"""Core data models for the game engine.
+
+All models are plain dataclasses. ``Player`` is mutable (the engine applies
+deltas in place); the static content models (``Monster``, ``Item``,
+``TerrainDef``, ``LocationDef``, ``Zone``) are frozen.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from enum import StrEnum
+
+
+class Mode(StrEnum):
+    """Which interaction surface the player is currently on."""
+
+    TILE = "tile"
+    MENU = "menu"
+
+
+class Slot(StrEnum):
+    """Equipment / item slot kinds."""
+
+    WEAPON = "weapon"
+    ARMOR = "armor"
+    CONSUMABLE = "consumable"
+    # v0.10 forge ore: a crafting MATERIAL carried in the satchel and spent at
+    # the forge. It is never equipped, never quaffed (no atk/def/heal), and
+    # never sold or bought — ore is earned in combat, not traded.
+    MATERIAL = "material"
+
+
+@dataclass(slots=True)
+class Player:
+    """A single adventurer's durable state.
+
+    Coordinates are map cells; ``mode`` and ``at_location`` track whether
+    the player is on the overworld or inside a location menu. Turn fields
+    gate the daily action budget; bestow fields gate the daily fortune pool.
+    """
+
+    name: str
+    x: int
+    y: int
+    hp: int
+    max_hp: int
+    level: int
+    xp: int
+    gold: int
+    atk: int
+    def_: int
+    weapon_id: str
+    armor_id: str
+    turns_left: int
+    turn_day: int
+    mode: Mode
+    at_location: str
+    created_at: str
+    last_seen: str
+    log_cursor: int
+    bestow_spent: int
+    bestow_day: int
+    wins: int = 0
+    posts_sent: int = 0
+    post_day: int = 0
+    gambles: int = 0
+    gamble_day: int = 0
+    # v0.7 "depth below" retention columns: how far the dungeon has been
+    # plumbed (0 = never descended; N = cleared rung N, 1-indexed), the
+    # carried satchel (see below), and the enhancement plus on whichever
+    # weapon/armour is CURRENTLY equipped in each slot.
+    deepest_rung: int = 0
+    # v0.10 STACK-BASED satchel: comma-joined "id:qty" stacks ('' = empty),
+    # e.g. "minor_potion:3,iron_ore:5". ``satchel_max`` caps DISTINCT stacks,
+    # not total items; per-stack qty is unbounded. Replaces the v0.7 flat id
+    # list. The "id:qty" wire format is owned by understone.engine.satchel
+    # (decode_satchel/encode_satchel); every reader goes through that codec.
+    satchel: str = ""
+    weapon_plus: int = 0
+    armor_plus: int = 0
+    # v0.10 the Vault: gold banked at the inn. SAFE from ambush (the steal only
+    # ever touches carried ``gold``) and SURVIVES the Wyrm-win legacy reset (a
+    # small persistent reward across runs, like a win ★).
+    banked: int = 0
+
+
+@dataclass(frozen=True, slots=True)
+class Monster:
+    """A static monster definition from the content pack.
+
+    ``boss`` monsters are the fixed endgame foe (the Wyrm Below): they are
+    excluded from random tier-band selection and only ever faced through the
+    deliberate ``challenge`` verb.
+    """
+
+    tier: int
+    name: str
+    hp: int
+    atk: int
+    def_: int
+    xp: int
+    gold: int
+    monster_id: str = ""
+    boss: bool = False
+    # v0.7 weighted forest encounters: ``weight`` biases the random pick (a
+    # low weight surfaces seldom), ``rare`` marks a named beast that fires a
+    # public Herald flash and drops a guaranteed draught on the kill. Rung
+    # guardians ignore both (a rung is a fixed foe, never a weighted roll).
+    weight: int = 10
+    rare: bool = False
+
+
+@dataclass(frozen=True, slots=True)
+class Item:
+    """A static item / equipment definition from the content pack."""
+
+    item_id: str
+    name: str
+    slot: Slot
+    atk: int
+    def_: int
+    heal: int
+    price: int
+
+
+@dataclass(frozen=True, slots=True)
+class TerrainDef:
+    """A terrain kind: its glyph, walkability, encounter rate, colour role."""
+
+    key: str
+    glyph: str
+    walkable: bool
+    encounter_rate: float
+    color: str
+
+
+@dataclass(frozen=True, slots=True)
+class LocationDef:
+    """A named location placed on the map (inn, shop, healer, dungeon)."""
+
+    key: str
+    kind: str
+    name: str
+    x: int
+    y: int
+    glyph: str
+    color: str
+    actions: tuple[str, ...]
+    flavor: tuple[str, ...] = field(default_factory=tuple)
+
+
+@dataclass(frozen=True, slots=True)
+class Zone:
+    """A rectangular region that biases which monster tiers spawn."""
+
+    key: str
+    x0: int
+    y0: int
+    x1: int
+    y1: int
+    tier_lo: int
+    tier_hi: int
+
+    def contains(self, x: int, y: int) -> bool:
+        """Return whether ``(x, y)`` falls inside this zone's rectangle."""
+        return self.x0 <= x <= self.x1 and self.y0 <= y <= self.y1
+
+
+@dataclass(frozen=True, slots=True)
+class WorldEvent:
+    """One row of the weighted overworld encounter table.
+
+    ``kind`` is one of ``fight``/``gold``/``heal``/``trap``/``lore``.
+    ``weight`` biases random selection. ``lo``/``hi`` bound the rolled amount
+    for the value-bearing kinds (gold/heal/trap); they are unused for
+    ``fight`` (the foe comes from the zone band) and ``lore`` (pure flavour).
+    """
+
+    kind: str
+    weight: int
+    text: str
+    lo: int
+    hi: int
+
+
+@dataclass(frozen=True, slots=True)
+class Settings:
+    """Economy and progression parameters sourced from the content pack."""
+
+    daily_turns: int
+    rest_cost: int
+    heal_cost_per_hp: int
+    starting_gold: int
+    starting_weapon: str
+    starting_armor: str
+    start_hp: int
+    start_atk: int
+    start_def: int
+    xp_base: int
+    growth_max_hp: int
+    growth_atk: int
+    growth_def: int
+    bestow_daily_budget: int
+    dungeon_tiers: tuple[int, ...]
+    boss_monster: str
+    wyrm_min_level: int
+    ambush_min_level: int
+    ambush_level_band: int
+    ambush_gold_pct: int
+    post_daily_cap: int
+    gamble_max_bet: int
+    gamble_daily_cap: int
+    # v0.7 "depth below": the carried-potion satchel size, the forge cost
+    # ladder (base * (current_plus + 1)) and its enhancement ceiling, and the
+    # consumable item a rare beast is guaranteed to drop on its kill.
+    satchel_max: int
+    forge_base_cost: int
+    forge_max_plus: int
+    rare_drop_item: str
+    # v0.10 the ore-gated forge: the world's forge MATERIAL item id (validated
+    # to slot=material), the ore each +1 step costs (need = (plus + 1) *
+    # per_plus), and the two ore sources — a guaranteed drop on a won dungeon
+    # rung and a chance of one ore on a won forest fight. Ore is combat-earned,
+    # never purchasable; the forge spends gold AND ore.
+    forge_ore_item: str
+    forge_ore_per_plus: int
+    ore_dungeon_drop: int
+    ore_forest_chance: float
+    # v0.8 "worlds without authors": the Watch's per-world CRT palette. One of
+    # the names in WATCH_THEMES; defaults to "phosphor" (the original green), so
+    # a pack that omits it looks exactly as the Vale always has.
+    watch_theme: str = "phosphor"

examples/door-game/understone/engine/movement.py

@@ -0,0 +1,223 @@
+"""Overworld movement resolution.
+
+Movement walks tile by tile so each intermediate cell is checked for
+walls/edges and rolls an encounter. When a roll fires it weighted-picks one
+row from the world's event table. A ``fight`` row STOPS the walk (a wandering
+monster bars the path); the value-bearing rows (gold/heal/trap) and pure
+``lore`` are applied immediately and the walk continues — but only one event
+fires per walk, so once any row has fired no further cells roll.
+
+The walk stops early on the first of: running out of steps, hitting a blocked
+cell, stepping onto a location door (flips to MENU), or a ``fight`` encounter.
+
+Movement spends no daily turns — only fighting does. Gold/heal/trap deltas are
+applied straight to the player here (movement already mutates the player's
+position), floored/capped so a trap never kills and a spring never overfills.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING
+
+from understone.engine.models import Mode
+
+if TYPE_CHECKING:
+    from understone.engine.models import Player, WorldEvent
+    from understone.engine.rng import GameRNG
+    from understone.engine.world import World
+
+MAX_STEPS = 8
+
+_DELTAS: dict[str, tuple[int, int]] = {
+    "N": (0, -1),
+    "S": (0, 1),
+    "E": (1, 0),
+    "W": (-1, 0),
+}
+
+_HEADINGS: dict[str, str] = {
+    "north": "N",
+    "south": "S",
+    "east": "E",
+    "west": "W",
+    "n": "N",
+    "s": "S",
+    "e": "E",
+    "w": "W",
+}
+
+
+@dataclass(slots=True)
+class MoveEvent:
+    """A non-fight overworld event already applied to the player.
+
+    ``kind`` is ``gold``/``heal``/``trap``/``lore``; ``text`` is the pack's
+    flavour line; ``amount`` is the rolled magnitude (0 for ``lore``). The
+    player's hp/gold have already been mutated by ``resolve_move`` — this
+    record exists only so the façade can narrate what happened.
+    """
+
+    kind: str
+    text: str
+    amount: int = 0
+
+
+@dataclass(slots=True)
+class MoveResult:
+    """Outcome of a movement attempt.
+
+    ``steps_taken`` counts cells actually entered. ``blocked`` is set when a
+    wall/edge stopped the walk. ``entered_location`` carries a location key
+    when the walk ended on a door. ``pending_fight`` carries an opponent
+    tier band when a ``fight`` encounter interrupted the walk. ``event``
+    carries a non-fight overworld event (already applied) when one fired.
+    """
+
+    steps_taken: int
+    blocked: bool = False
+    blocked_reason: str = ""
+    entered_location: str | None = None
+    pending_fight: tuple[int, int] | None = None
+    event: MoveEvent | None = None
+    path_notes: list[str] = field(default_factory=list)
+
+
+def parse_directions(steps: str, heading: str, distance: int) -> list[str]:
+    """Translate either input form into a clamped list of cardinal steps.
+
+    The ``steps`` string (e.g. ``"NNEE"``) takes precedence when non-empty;
+    otherwise ``heading`` + ``distance`` is expanded. Either way the result
+    is clamped to ``MAX_STEPS``. Unknown direction characters are rejected.
+    """
+    raw = steps.strip().upper()
+    if raw:
+        dirs: list[str] = []
+        for ch in raw:
+            if ch not in _DELTAS:
+                raise ValueError(f"unknown direction {ch!r} (use N/S/E/W)")
+            dirs.append(ch)
+        return dirs[:MAX_STEPS]
+
+    head = heading.strip().lower()
+    if not head:
+        return []
+    if head not in _HEADINGS:
+        raise ValueError(f"unknown heading {heading!r} (use north/south/east/west)")
+    count = max(0, min(distance, MAX_STEPS))
+    return [_HEADINGS[head]] * count
+
+
+def resolve_move(
+    world: World,
+    player: Player,
+    rng: GameRNG,
+    *,
+    steps: str = "",
+    heading: str = "",
+    distance: int = 1,
+    max_steps: int = MAX_STEPS,
+) -> MoveResult:
+    """Walk *player* across *world* one cell at a time, mutating position.
+
+    Stops at the first blocking edge/wall, location door, or encounter.
+    Returns a :class:`MoveResult` describing where and why the walk ended.
+    """
+    directions = parse_directions(steps, heading, distance)[:max_steps]
+    result = MoveResult(steps_taken=0)
+    fired = False  # at most one overworld event per walk
+
+    for direction in directions:
+        dx, dy = _DELTAS[direction]
+        nx, ny = player.x + dx, player.y + dy
+
+        if not world.in_bounds(nx, ny):
+            result.blocked = True
+            result.blocked_reason = "the edge of the known world"
+            break
+        if not world.is_walkable(nx, ny):
+            terrain = world.terrain_at(nx, ny)
+            result.blocked = True
+            result.blocked_reason = _blocked_phrase(terrain.key)
+            break
+
+        player.x, player.y = nx, ny
+        result.steps_taken += 1
+
+        location = world.location_at(nx, ny)
+        if location is not None:
+            player.mode = Mode.MENU
+            player.at_location = location.key
+            result.entered_location = location.key
+            break
+
+        if fired:
+            continue
+        band = _encounter_band(world, nx, ny)
+        if band is None:
+            continue
+        terrain = world.terrain_at(nx, ny)
+        if not rng.chance(terrain.encounter_rate):
+            continue
+        fired = True
+        picked = _pick_event(world, rng)
+        if picked is None or picked.kind == "fight":
+            result.pending_fight = band
+            break
+        result.event = _apply_event(player, rng, picked)
+
+    return result
+
+
+def _pick_event(world: World, rng: GameRNG) -> WorldEvent | None:
+    """Weighted-pick one row from the world's event table, or ``None``.
+
+    Returns ``None`` only when the pack ships no event table at all, in which
+    case the caller falls back to the legacy always-a-fight behaviour.
+    """
+    weights = world.event_weights()
+    if not weights:
+        return None
+    return world.events[rng.weighted_index(weights)]
+
+
+def _apply_event(player: Player, rng: GameRNG, event: WorldEvent) -> MoveEvent:
+    """Apply a non-fight event to *player* and return a record for narration.
+
+    ``gold`` credits a rolled amount; ``heal`` adds hp capped at ``max_hp``;
+    ``trap`` subtracts hp floored at 1 (a trap never kills, and never touches
+    gold); ``lore`` mutates nothing. Amounts roll over ``[lo, hi]``.
+    """
+    if event.kind == "lore":
+        return MoveEvent(kind="lore", text=event.text)
+    amount = rng.randint(event.lo, event.hi)
+    if event.kind == "gold":
+        player.gold += amount
+    elif event.kind == "heal":
+        amount = min(amount, player.max_hp - player.hp)
+        player.hp += amount
+    elif event.kind == "trap":
+        amount = min(amount, max(player.hp - 1, 0))
+        player.hp -= amount
+    return MoveEvent(kind=event.kind, text=event.text, amount=amount)
+
+
+def _encounter_band(world: World, x: int, y: int) -> tuple[int, int] | None:
+    """Return the tier band for an encounter at ``(x, y)``, or ``None``.
+
+    Encounters only happen inside a zone; open terrain with no zone is safe.
+    """
+    zone = world.zone_for(x, y)
+    if zone is None:
+        return None
+    return (zone.tier_lo, zone.tier_hi)
+
+
+def _blocked_phrase(terrain_key: str) -> str:
+    """Return an in-fiction phrase for being blocked by *terrain_key*."""
+    phrases = {
+        "water": "deep water",
+        "tree": "an impassable thicket",
+        "wall": "a sheer wall",
+    }
+    return phrases.get(terrain_key, "rough ground")

examples/door-game/understone/engine/rank.py

@@ -0,0 +1,42 @@
+"""Leaderboard ordering.
+
+Adventurers are ranked by level (desc), then XP (desc), then name (asc)
+so ties break deterministically and alphabetically. The Hall of Legends is a
+separate, append-only roll of completed runs (Wyrm kills), ordered newest
+first by the store.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True, slots=True)
+class RankEntry:
+    """One row of the leaderboard.
+
+    ``wins`` is the number of times the adventurer has slain the Wyrm Below
+    (each shown as a ★ beside the name); it does not affect ordering.
+    """
+
+    name: str
+    level: int
+    xp: int
+    gold: int
+    wins: int = 0
+
+
+@dataclass(frozen=True, slots=True)
+class HallEntry:
+    """One immortalised run in the Hall of Legends (a Wyrm slain)."""
+
+    name: str
+    win_ts: str
+    run_days: int
+    level_at_win: int
+
+
+def leaderboard(entries: list[RankEntry], limit: int = 10) -> list[RankEntry]:
+    """Return the top ``limit`` entries in leaderboard order."""
+    ordered = sorted(entries, key=lambda e: (-e.level, -e.xp, e.name))
+    return ordered[:limit]

examples/door-game/understone/engine/rng.py

@@ -0,0 +1,58 @@
+"""Randomness with deterministic test injection.
+
+A single master ``GameRNG`` is seeded once at startup (from ``os.urandom``
+in production). Per-encounter child generators are derived from the master
+so a fight's rolls are reproducible given the same child seed. No tool
+argument ever carries a seed — randomness is server-authoritative.
+"""
+
+from __future__ import annotations
+
+import os
+import random
+
+
+class GameRNG:
+    """A thin wrapper over ``random.Random`` with child-RNG derivation."""
+
+    def __init__(self, seed: int | None = None) -> None:
+        if seed is None:
+            seed = int.from_bytes(os.urandom(8), "big")
+        self._random = random.Random(seed)
+
+    def chance(self, probability: float) -> bool:
+        """Return ``True`` with the given probability in ``[0.0, 1.0]``."""
+        if probability <= 0.0:
+            return False
+        if probability >= 1.0:
+            return True
+        return self._random.random() < probability
+
+    def randint(self, lo: int, hi: int) -> int:
+        """Return a random integer in the inclusive range ``[lo, hi]``."""
+        return self._random.randint(lo, hi)
+
+    def choice_index(self, count: int) -> int:
+        """Return a random index in ``[0, count)``."""
+        return self._random.randrange(count)
+
+    def weighted_index(self, weights: list[int]) -> int:
+        """Return an index into ``weights`` chosen in proportion to them.
+
+        A single uniform draw is mapped through the cumulative sum, so the
+        result is deterministic under a fixed seed. ``weights`` must be
+        non-empty with a positive total (the loader guarantees this for the
+        content pack's event table).
+        """
+        total = sum(weights)
+        roll = self._random.randrange(total)
+        cumulative = 0
+        for index, weight in enumerate(weights):
+            cumulative += weight
+            if roll < cumulative:
+                return index
+        return len(weights) - 1
+
+    def child(self) -> GameRNG:
+        """Derive an independent child RNG seeded from the master stream."""
+        return GameRNG(self._random.getrandbits(64))

examples/door-game/understone/engine/satchel.py

@@ -0,0 +1,62 @@
+"""The satchel wire codec — the one home for the ``"id:qty"`` stack encoding.
+
+A player's satchel is stored as a single string: comma-joined ``id:qty`` stacks,
+e.g. ``"minor_potion:3,iron_ore:5"``; an empty string is an empty bag. This
+module is the SINGLE source of truth for that format. Three readers carried a
+byte-identical decode loop (the game façade, the Watch payload builder, and the
+balance simulator); they all delegate here so the format is described — and
+parsed — in exactly one place.
+
+The codec is pure and stdlib-only: it knows the wire shape and nothing else.
+It does NOT collapse duplicate ids into one stack, resolve ids against a content
+pack, or enforce the distinct-stack cap — those are stack *semantics* the
+callers own. The codec only encodes and decodes.
+"""
+
+from __future__ import annotations
+
+
+def decode_satchel(s: str) -> list[tuple[str, int]]:
+    """Decode the ``"id:qty"`` satchel string into ordered ``(item_id, qty)`` stacks.
+
+    Splits on ``","`` and skips empty chunks (so an empty string, a leading or
+    trailing comma, and a doubled comma all yield no spurious stack). Each chunk
+    is partitioned on ``":"``:
+
+    * a chunk with no colon (a bare id) parses as quantity ``1`` — a colonless
+      fragment is treated as a single item, never silently dropped;
+    * a chunk whose quantity is present but not an integer, or is ``<= 0``, is
+      skipped;
+    * a chunk with an empty id is skipped.
+
+    Order is preserved (first-stowed first), which fixes which potion a heal tie
+    resolves to. The codec collapses nothing — callers own stack semantics.
+    """
+    stacks: list[tuple[str, int]] = []
+    for chunk in s.split(","):
+        if not chunk:
+            continue
+        item_id, sep, qty_str = chunk.partition(":")
+        if not item_id:
+            continue
+        if not sep:
+            # A bare id with no colon is a single item (defensive: never drop it).
+            stacks.append((item_id, 1))
+            continue
+        try:
+            qty = int(qty_str)
+        except ValueError:
+            continue
+        if qty > 0:
+            stacks.append((item_id, qty))
+    return stacks
+
+
+def encode_satchel(stacks: list[tuple[str, int]]) -> str:
+    """Encode ``(item_id, qty)`` stacks back into the comma-joined ``"id:qty"`` string.
+
+    Any stack at quantity ``<= 0`` is dropped, so the encoding never emits
+    ``"id:0"``; this is the single home for the drop-at-empty rule, letting
+    callers decrement freely and rely on a spent-to-zero stack falling away.
+    """
+    return ",".join(f"{item_id}:{qty}" for item_id, qty in stacks if qty > 0)

examples/door-game/understone/engine/textwidth.py

@@ -0,0 +1,99 @@
+"""The one-glyph-one-column contract for everything drawn on the grid.
+
+Every surface Understone paints — the bordered text frames, the golden frames
+the screen tests pin, and the Watch's CSS ``1ch``-per-cell map — assumes each
+map glyph occupies *exactly one* terminal column. A glyph that renders two
+columns (a CJK ideograph, an emoji) shoves the row right and tears the
+box-drawing border; a zero-width combining mark stacks onto its neighbour and
+desynchronises the column count the other way. :func:`is_grid_safe` is the
+single predicate that admits a character to the grid, and :data:`SAFE_PALETTE`
+is the curated set of glyphs known to satisfy it with period CP437 flavour.
+
+THE WESTERN-MONOSPACE ASSUMPTION. Width here is judged for the Western
+monospace metrics every Understone surface actually uses — the pinned Watch
+font stack and the monospace of a chat client's code block. Under those
+metrics the East-Asian-Width *Ambiguous* class renders single-column, and
+Ambiguous is the CP437 heartland: ``█ ♣ ↑ ∩ ≈ ★`` are all EAW=A. So the rule
+bars only the genuinely double-width classes — Wide (``W``) and Fullwidth
+(``F``) — and admits Ambiguous, Narrow, Neutral, and Halfwidth. The trade is
+deliberate: on a CJK-width terminal an Ambiguous glyph would take two columns,
+but Understone's surfaces are not those terminals.
+"""
+
+from __future__ import annotations
+
+import unicodedata
+
+# East-Asian-Width classes that render two columns under Western monospace and
+# would therefore tear a frame; everything else (Na/N/H/A) renders one column.
+_DOUBLE_WIDTH_EAW = frozenset({"W", "F"})
+
+# Unicode general categories that carry no column of their own — combining
+# marks (Mn/Mc/Me) stack onto a neighbour, format/control codes (Cf/Cc) are
+# invisible — so a single such code point is not a paintable cell.
+_ZERO_WIDTH_CATEGORIES = frozenset({"Mn", "Mc", "Me", "Cf", "Cc"})
+
+
+def is_grid_safe(ch: str) -> bool:
+    """Return whether *ch* may occupy a single grid cell.
+
+    A grid-safe character is exactly one code point, is printable, is not an
+    East-Asian Wide or Fullwidth glyph (the only classes that render two
+    columns under the Western monospace metrics our surfaces use — see the
+    module docstring), and is not a combining mark or format/control code (a
+    zero-width code point that would desynchronise the column count).
+    """
+    if len(ch) != 1:
+        return False
+    if not ch.isprintable():
+        return False
+    if unicodedata.east_asian_width(ch) in _DOUBLE_WIDTH_EAW:
+        return False
+    return unicodedata.category(ch) not in _ZERO_WIDTH_CATEGORIES
+
+
+# A curated set of single-column glyphs with BBS / CP437 character, grouped by
+# the role an author is likely to want them for. Every entry is grid-safe AND
+# free of the loader's reserved markers (two tests assert both), so a pack
+# author can pull any of these for terrain, structures, or actors without
+# risking a torn frame or colliding with the '@'/'☻' player markers. The black
+# smiling face (☻) is the other-player marker and so is NOT here; its white
+# twin (☺) is a free being glyph. The grouping is documentation; the set is
+# what callers iterate.
+SAFE_PALETTE: tuple[str, ...] = (
+    # terrain
+    "≋",
+    "≈",
+    "░",
+    "▒",
+    "▓",
+    "♣",
+    "↑",
+    "▲",
+    ".",
+    ",",
+    "'",
+    '"',
+    "=",
+    "~",
+    "§",
+    "ø",
+    "¤",
+    "Ω",
+    # structures
+    "⌂",
+    "✚",
+    "∩",
+    "†",
+    "‡",
+    "$",
+    "◊",
+    "☖",
+    # beings
+    "☺",
+    "¶",
+    # misc
+    "•",
+    "⁂",
+    "★",
+)

examples/door-game/understone/engine/turns.py

@@ -0,0 +1,65 @@
+"""Daily action budget and the UTC-day rollover.
+
+Turns refresh lazily: the first action on a new UTC day resets the
+budget rather than relying on a scheduled job. The same rollover resets
+the per-player bestow pool and the social daily caps (posts left, dice
+played), so every daily allowance shares one boundary. The clock is
+injected so tests can cross midnight deterministically.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+    from datetime import datetime
+
+    from understone.engine.models import Player
+
+
+def _utc_ordinal(clock: Callable[[], datetime]) -> int:
+    """Return today's proleptic-Gregorian ordinal in UTC."""
+    return clock().toordinal()
+
+
+def ensure_day(player: Player, clock: Callable[[], datetime], daily_turns: int) -> bool:
+    """Refresh daily allowances if the UTC day has advanced.
+
+    Returns ``True`` when a reset occurred. On a new UTC day this resets the
+    turn budget (to *daily_turns*), the bestow pool, the daily post count, and
+    the daily dice count — each back to its baseline — stamping the current UTC
+    ordinal onto every day marker. Each counter is reset independently so a
+    stale stamp on one never suppresses the refresh of another.
+    """
+    today = _utc_ordinal(clock)
+    reset = False
+    if player.turn_day != today:
+        player.turns_left = daily_turns
+        player.turn_day = today
+        reset = True
+    if player.bestow_day != today:
+        player.bestow_spent = 0
+        player.bestow_day = today
+        reset = True
+    if player.post_day != today:
+        player.posts_sent = 0
+        player.post_day = today
+        reset = True
+    if player.gamble_day != today:
+        player.gambles = 0
+        player.gamble_day = today
+        reset = True
+    return reset
+
+
+def spend_turn(player: Player) -> bool:
+    """Consume one daily turn.
+
+    Returns ``True`` and decrements when a turn is available; returns
+    ``False`` and leaves state untouched when the budget is exhausted.
+    """
+    if player.turns_left <= 0:
+        return False
+    player.turns_left -= 1
+    return True

examples/door-game/understone/engine/world.py

@@ -0,0 +1,117 @@
+"""Runtime world model — terrain, locations, zones, content tables, settings.
+
+Built by ``world.loader`` from JSON. The engine queries this for
+walkability, encounter rates, location lookups, and tier-banded monster
+selection. It holds no mutable game state.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from understone.engine.models import (
+        Item,
+        LocationDef,
+        Monster,
+        Settings,
+        TerrainDef,
+        WorldEvent,
+        Zone,
+    )
+
+
+class World:
+    """An immutable-after-construction view of the game map and content."""
+
+    def __init__(
+        self,
+        *,
+        name: str,
+        width: int,
+        height: int,
+        spawn: tuple[int, int],
+        terrain: list[list[TerrainDef]],
+        locations: list[LocationDef],
+        zones: list[Zone],
+        monsters: list[Monster],
+        items: list[Item],
+        settings: Settings,
+        events: list[WorldEvent] | None = None,
+    ) -> None:
+        self.name = name
+        self.width = width
+        self.height = height
+        self.spawn = spawn
+        self.terrain = terrain
+        self.locations = locations
+        self.zones = zones
+        self.monsters = monsters
+        self.items = items
+        self.settings = settings
+        self.events: list[WorldEvent] = events or []
+        self._event_weights: list[int] = [e.weight for e in self.events]
+        self._loc_by_xy: dict[tuple[int, int], LocationDef] = {
+            (loc.x, loc.y): loc for loc in locations
+        }
+        self._loc_by_key: dict[str, LocationDef] = {loc.key: loc for loc in locations}
+        self._item_by_id: dict[str, Item] = {it.item_id: it for it in items}
+        self._monster_by_id: dict[str, Monster] = {
+            m.monster_id: m for m in monsters if m.monster_id
+        }
+
+    def in_bounds(self, x: int, y: int) -> bool:
+        """Return whether ``(x, y)`` is inside the map rectangle."""
+        return 0 <= x < self.width and 0 <= y < self.height
+
+    def terrain_at(self, x: int, y: int) -> TerrainDef:
+        """Return the terrain definition at ``(x, y)`` (caller bounds-checks)."""
+        return self.terrain[y][x]
+
+    def location_at(self, x: int, y: int) -> LocationDef | None:
+        """Return the location placed at ``(x, y)``, if any."""
+        return self._loc_by_xy.get((x, y))
+
+    def location_by_key(self, key: str) -> LocationDef | None:
+        """Return the location with the given key, if any."""
+        return self._loc_by_key.get(key)
+
+    def item_by_id(self, item_id: str) -> Item | None:
+        """Return the item with the given id, if any."""
+        return self._item_by_id.get(item_id)
+
+    def monster_by_id(self, monster_id: str) -> Monster | None:
+        """Return the monster with the given id, if any (boss lookup)."""
+        return self._monster_by_id.get(monster_id)
+
+    def event_weights(self) -> list[int]:
+        """Return the parallel weight list for the overworld event table."""
+        return self._event_weights
+
+    def is_walkable(self, x: int, y: int) -> bool:
+        """Return whether a player may stand on ``(x, y)``.
+
+        Out-of-bounds is never walkable. A location tile is always walkable
+        regardless of its underlying terrain (you can step onto the door).
+        """
+        if not self.in_bounds(x, y):
+            return False
+        if (x, y) in self._loc_by_xy:
+            return True
+        return self.terrain[y][x].walkable
+
+    def zone_for(self, x: int, y: int) -> Zone | None:
+        """Return the first zone whose rectangle contains ``(x, y)``."""
+        for zone in self.zones:
+            if zone.contains(x, y):
+                return zone
+        return None
+
+    def monsters_for_tier_band(self, lo: int, hi: int) -> list[Monster]:
+        """Return non-boss monsters whose tier falls within ``[lo, hi]``.
+
+        Boss monsters (the Wyrm Below) are never returned: they are the fixed
+        endgame foe, faced only through the deliberate ``challenge`` verb, and
+        must never surface as a random encounter or a dungeon-gauntlet rung.
+        """
+        return [m for m in self.monsters if lo <= m.tier <= hi and not m.boss]

examples/door-game/understone/errors.py

@@ -0,0 +1,24 @@
+"""Shared exception types for Understone.
+
+These never cross the MCP boundary — the server layer catches everything
+and renders an in-fiction line — but they let internal layers fail with a
+readable, specific message.
+"""
+
+from __future__ import annotations
+
+
+class UnderstoneError(Exception):
+    """Base class for all Understone errors."""
+
+
+class WorldLoadError(UnderstoneError):
+    """Raised when a content pack fails to parse or validate.
+
+    The message is written to be readable by a pack author: it names the
+    file, the offending field, and what was expected.
+    """
+
+
+class PersistenceError(UnderstoneError):
+    """Raised when the save store cannot be opened or migrated."""

examples/door-game/understone/persistence.py

@@ -0,0 +1,391 @@
+"""SQLite persistence — the only storage layer, ``sqlite3`` only.
+
+A single connection is held for the process lifetime. MCP tool handlers are
+synchronous and run on one event-loop thread, so writes serialise naturally
+and no connection pool or lock is needed [VERIFIED: handlers are sync def].
+WAL journaling is enabled so reads never block the single writer.
+
+The store loads all players and recent events into memory at construction
+(a write-through cache). State-changing tools update the cache and the DB in
+one transaction; the game façade owns the per-action commit policy.
+
+The connection is opened with ``check_same_thread=False`` because the Store
+may be CONSTRUCTED on a different thread than the event-loop thread that later
+serves tools (both the test fixture and ``main`` do this). Post-construction
+access is single-threaded: sync tools run inline on the loop [verified against
+mcp 1.27 func_metadata], so writes still serialise without a lock.
+"""
+
+from __future__ import annotations
+
+import sqlite3
+from typing import TYPE_CHECKING
+
+from understone.engine.log import Event
+from understone.engine.models import Mode, Player
+from understone.engine.rank import HallEntry, RankEntry
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+# Pre-1.0 the schema mutates in place and the stamp is not yet meaningful;
+# version discipline (and migrations) begins at 1.0.
+_SCHEMA_VERSION = 1
+
+# How many of the newest events to hydrate at construction. Full history stays
+# in SQLite; this bounds the in-memory tail. Single source of truth — game.py
+# imports it for the runtime trim, so the load size and the trim size cannot
+# diverge. An ops knob (memory ceiling), never an economy value.
+EVENT_TAIL_KEEP = 500
+
+_PLAYER_COLUMNS = (
+    "name",
+    "x",
+    "y",
+    "hp",
+    "max_hp",
+    "level",
+    "xp",
+    "gold",
+    "atk",
+    "def_",
+    "weapon_id",
+    "armor_id",
+    "turns_left",
+    "turn_day",
+    "mode",
+    "at_location",
+    "created_at",
+    "last_seen",
+    "log_cursor",
+    "bestow_spent",
+    "bestow_day",
+    "wins",
+    "posts_sent",
+    "post_day",
+    "gambles",
+    "gamble_day",
+    "deepest_rung",
+    "satchel",
+    "weapon_plus",
+    "armor_plus",
+    "banked",
+)
+
+
+class Store:
+    """A write-through SQLite store for players and the shared event log."""
+
+    def __init__(self, db_path: str | Path) -> None:
+        self._conn = sqlite3.connect(str(db_path), check_same_thread=False)
+        self._conn.row_factory = sqlite3.Row
+        self._conn.execute("PRAGMA journal_mode=WAL")
+        self._conn.execute("PRAGMA foreign_keys=ON")
+        self._init_schema()
+
+    # -- schema ----------------------------------------------------------
+
+    def _init_schema(self) -> None:
+        self._conn.executescript(
+            """
+            CREATE TABLE IF NOT EXISTS players (
+                name        TEXT PRIMARY KEY,
+                x           INTEGER NOT NULL,
+                y           INTEGER NOT NULL,
+                hp          INTEGER NOT NULL,
+                max_hp      INTEGER NOT NULL,
+                level       INTEGER NOT NULL,
+                xp          INTEGER NOT NULL,
+                gold        INTEGER NOT NULL,
+                atk         INTEGER NOT NULL,
+                def_        INTEGER NOT NULL,
+                weapon_id   TEXT NOT NULL,
+                armor_id    TEXT NOT NULL,
+                turns_left  INTEGER NOT NULL,
+                turn_day    INTEGER NOT NULL,
+                mode        TEXT NOT NULL,
+                at_location TEXT NOT NULL,
+                created_at  TEXT NOT NULL,
+                last_seen   TEXT NOT NULL,
+                log_cursor  INTEGER NOT NULL,
+                bestow_spent INTEGER NOT NULL,
+                bestow_day  INTEGER NOT NULL,
+                wins        INTEGER NOT NULL DEFAULT 0,
+                posts_sent  INTEGER NOT NULL DEFAULT 0,
+                post_day    INTEGER NOT NULL DEFAULT 0,
+                gambles     INTEGER NOT NULL DEFAULT 0,
+                gamble_day  INTEGER NOT NULL DEFAULT 0,
+                deepest_rung INTEGER NOT NULL DEFAULT 0,
+                satchel     TEXT NOT NULL DEFAULT '',
+                weapon_plus INTEGER NOT NULL DEFAULT 0,
+                armor_plus  INTEGER NOT NULL DEFAULT 0,
+                banked      INTEGER NOT NULL DEFAULT 0
+            );
+
+            CREATE TABLE IF NOT EXISTS events (
+                id     INTEGER PRIMARY KEY AUTOINCREMENT,
+                ts     TEXT NOT NULL,
+                actor  TEXT NOT NULL,
+                kind   TEXT NOT NULL,
+                text   TEXT NOT NULL,
+                target TEXT NOT NULL DEFAULT ''
+            );
+
+            CREATE TABLE IF NOT EXISTS ambushes (
+                attacker TEXT NOT NULL,
+                target   TEXT NOT NULL,
+                day      INTEGER NOT NULL,
+                PRIMARY KEY (attacker, target, day)
+            );
+
+            CREATE TABLE IF NOT EXISTS hall_of_fame (
+                id           INTEGER PRIMARY KEY AUTOINCREMENT,
+                name         TEXT NOT NULL,
+                win_ts       TEXT NOT NULL,
+                run_days     INTEGER NOT NULL,
+                level_at_win INTEGER NOT NULL
+            );
+
+            CREATE TABLE IF NOT EXISTS meta (
+                key   TEXT PRIMARY KEY,
+                value TEXT NOT NULL
+            );
+            """
+        )
+        self._conn.execute(
+            "INSERT OR IGNORE INTO meta(key, value) VALUES('schema_version', ?)",
+            (str(_SCHEMA_VERSION),),
+        )
+        self._conn.commit()
+
+    def set_meta(self, key: str, value: str) -> None:
+        """Upsert a meta key (e.g. ``world_name``) and commit."""
+        self._conn.execute(
+            "INSERT INTO meta(key, value) VALUES(?, ?) "
+            "ON CONFLICT(key) DO UPDATE SET value=excluded.value",
+            (key, value),
+        )
+        self._conn.commit()
+
+    def get_meta(self, key: str) -> str | None:
+        """Return a meta value, or ``None`` if unset."""
+        row = self._conn.execute("SELECT value FROM meta WHERE key=?", (key,)).fetchone()
+        return None if row is None else str(row["value"])
+
+    # -- load ------------------------------------------------------------
+
+    def load_all(self) -> tuple[dict[str, Player], list[Event]]:
+        """Load every player and the most recent events into memory.
+
+        Only the newest ``EVENT_TAIL_KEEP`` events are resident; the full history
+        remains in SQLite. The tail is fetched newest-first then reversed so
+        the returned list stays ascending by id (the order ``since`` expects).
+        """
+        players = {
+            row["name"]: _row_to_player(row) for row in self._conn.execute("SELECT * FROM players")
+        }
+        rows = self._conn.execute(
+            "SELECT * FROM events ORDER BY id DESC LIMIT ?", (EVENT_TAIL_KEEP,)
+        ).fetchall()
+        events = [_row_to_event(row) for row in reversed(rows)]
+        return players, events
+
+    # -- writes (no commit here; the façade commits per action) ----------
+
+    def upsert_player(self, player: Player) -> None:
+        """Insert or update a player row (no commit)."""
+        placeholders = ", ".join("?" for _ in _PLAYER_COLUMNS)
+        assignments = ", ".join(f"{col}=excluded.{col}" for col in _PLAYER_COLUMNS if col != "name")
+        self._conn.execute(
+            f"INSERT INTO players ({', '.join(_PLAYER_COLUMNS)}) VALUES ({placeholders}) "
+            f"ON CONFLICT(name) DO UPDATE SET {assignments}",
+            _player_to_row(player),
+        )
+
+    def insert_event(self, ts: str, actor: str, kind: str, text: str, target: str = "") -> int:
+        """Append an event row (no commit) and return its new id.
+
+        ``target`` is empty for a public event or a player name for a private
+        note that only that player reads in their own catch-up.
+        """
+        cur = self._conn.execute(
+            "INSERT INTO events(ts, actor, kind, text, target) VALUES(?, ?, ?, ?, ?)",
+            (ts, actor, kind, text, target),
+        )
+        return int(cur.lastrowid or 0)
+
+    def insert_hall_row(self, name: str, win_ts: str, run_days: int, level_at_win: int) -> int:
+        """Append a Hall of Legends row (no commit) and return its new id."""
+        cur = self._conn.execute(
+            "INSERT INTO hall_of_fame(name, win_ts, run_days, level_at_win) VALUES(?, ?, ?, ?)",
+            (name, win_ts, run_days, level_at_win),
+        )
+        return int(cur.lastrowid or 0)
+
+    def record_ambush(self, attacker: str, target: str, day: int) -> None:
+        """Mark that *attacker* has spent their ambush on *target* for *day*.
+
+        Idempotent: the ``(attacker, target, day)`` primary key means a repeat
+        write is ignored, so re-recording the same attempt is harmless. No
+        commit — the façade folds this into the per-action transaction.
+        """
+        self._conn.execute(
+            "INSERT OR IGNORE INTO ambushes(attacker, target, day) VALUES(?, ?, ?)",
+            (attacker, target, day),
+        )
+
+    def has_ambushed(self, attacker: str, target: str, day: int) -> bool:
+        """Return whether *attacker* already ambushed *target* on *day*."""
+        row = self._conn.execute(
+            "SELECT 1 FROM ambushes WHERE attacker=? AND target=? AND day=?",
+            (attacker, target, day),
+        ).fetchone()
+        return row is not None
+
+    def commit(self) -> None:
+        """Commit the current transaction."""
+        self._conn.commit()
+
+    # -- read-only queries ----------------------------------------------
+
+    def top_ranks(self, limit: int = 10) -> list[RankEntry]:
+        """Return the leaderboard ordered by level, xp, then name."""
+        rows = self._conn.execute(
+            "SELECT name, level, xp, gold, wins FROM players "
+            "ORDER BY level DESC, xp DESC, name ASC LIMIT ?",
+            (limit,),
+        )
+        return [
+            RankEntry(
+                name=row["name"],
+                level=row["level"],
+                xp=row["xp"],
+                gold=row["gold"],
+                wins=row["wins"],
+            )
+            for row in rows
+        ]
+
+    def top_hall(self, limit: int = 5) -> list[HallEntry]:
+        """Return the most recent Hall of Legends rows, newest first."""
+        rows = self._conn.execute(
+            "SELECT name, win_ts, run_days, level_at_win FROM hall_of_fame "
+            "ORDER BY id DESC LIMIT ?",
+            (limit,),
+        )
+        return [
+            HallEntry(
+                name=row["name"],
+                win_ts=row["win_ts"],
+                run_days=row["run_days"],
+                level_at_win=row["level_at_win"],
+            )
+            for row in rows
+        ]
+
+    def targeted_events_since(self, viewer: str, cursor: int) -> list[Event]:
+        """Return *viewer*'s private notes past *cursor*, ascending by id.
+
+        Public history older than the resident tail is ephemeral by design (the
+        broadsheet does not keep), but private mail is durable: a note left while
+        the recipient was away must survive however many public events have since
+        pushed it out of the in-memory tail. The façade pulls the recipient's
+        targeted rows from SQLite to backfill that gap before rendering.
+        """
+        rows = self._conn.execute(
+            "SELECT * FROM events WHERE target=? AND id>? ORDER BY id",
+            (viewer, cursor),
+        ).fetchall()
+        return [_row_to_event(row) for row in rows]
+
+    def journal_mode(self) -> str:
+        """Return the active journal mode (for diagnostics / tests)."""
+        row = self._conn.execute("PRAGMA journal_mode").fetchone()
+        return str(row[0])
+
+    def close(self) -> None:
+        """Close the underlying connection."""
+        self._conn.close()
+
+
+def _player_to_row(player: Player) -> tuple[object, ...]:
+    return (
+        player.name,
+        player.x,
+        player.y,
+        player.hp,
+        player.max_hp,
+        player.level,
+        player.xp,
+        player.gold,
+        player.atk,
+        player.def_,
+        player.weapon_id,
+        player.armor_id,
+        player.turns_left,
+        player.turn_day,
+        str(player.mode),
+        player.at_location,
+        player.created_at,
+        player.last_seen,
+        player.log_cursor,
+        player.bestow_spent,
+        player.bestow_day,
+        player.wins,
+        player.posts_sent,
+        player.post_day,
+        player.gambles,
+        player.gamble_day,
+        player.deepest_rung,
+        player.satchel,
+        player.weapon_plus,
+        player.armor_plus,
+        player.banked,
+    )
+
+
+def _row_to_player(row: sqlite3.Row) -> Player:
+    return Player(
+        name=row["name"],
+        x=row["x"],
+        y=row["y"],
+        hp=row["hp"],
+        max_hp=row["max_hp"],
+        level=row["level"],
+        xp=row["xp"],
+        gold=row["gold"],
+        atk=row["atk"],
+        def_=row["def_"],
+        weapon_id=row["weapon_id"],
+        armor_id=row["armor_id"],
+        turns_left=row["turns_left"],
+        turn_day=row["turn_day"],
+        mode=Mode(row["mode"]),
+        at_location=row["at_location"],
+        created_at=row["created_at"],
+        last_seen=row["last_seen"],
+        log_cursor=row["log_cursor"],
+        bestow_spent=row["bestow_spent"],
+        bestow_day=row["bestow_day"],
+        wins=row["wins"],
+        posts_sent=row["posts_sent"],
+        post_day=row["post_day"],
+        gambles=row["gambles"],
+        gamble_day=row["gamble_day"],
+        deepest_rung=row["deepest_rung"],
+        satchel=row["satchel"],
+        weapon_plus=row["weapon_plus"],
+        armor_plus=row["armor_plus"],
+        banked=row["banked"],
+    )
+
+
+def _row_to_event(row: sqlite3.Row) -> Event:
+    return Event(
+        event_id=row["id"],
+        ts=row["ts"],
+        kind=row["kind"],
+        actor=row["actor"],
+        text=row["text"],
+        target=row["target"],
+    )

examples/door-game/understone/screen/__init__.py

@@ -0,0 +1,5 @@
+"""Screen layer — pure rendering of game state into text frames.
+
+No ANSI SGR escape sequences are emitted in v1; colour is carried as
+metadata on cells for a future renderer but never written to output.
+"""

examples/door-game/understone/screen/box.py

@@ -0,0 +1,35 @@
+"""Shared box-drawing glyphs and the title-in-border helper.
+
+The frame renderer and the menu renderer both draw a single box with a
+centred title in the top border. The glyph set and that border logic live
+here so the two renderers cannot drift apart.
+"""
+
+from __future__ import annotations
+
+TL = "┌"  # top-left corner
+TR = "┐"  # top-right corner
+BL = "└"  # bottom-left corner
+BR = "┘"  # bottom-right corner
+H = "─"  # horizontal run
+V = "│"  # vertical edge
+
+
+def border_with_title(inner: int, title: str) -> str:
+    """Build the top border ``┌──title──┐`` with the title centred in the run.
+
+    *inner* is the interior width (between the corners). The title is wrapped
+    in single spaces and centred; if it does not fit the run it is truncated.
+    An empty/blank title yields a plain horizontal run.
+    """
+    label = title.strip()
+    if not label:
+        return TL + (H * inner) + TR
+    framed = f" {label} "
+    if len(framed) > inner:
+        framed = framed[:inner]
+    pad = inner - len(framed)
+    left = pad // 2
+    right = pad - left
+    middle = (H * left) + framed + (H * right)
+    return TL + middle + TR

examples/door-game/understone/screen/grid.py

@@ -0,0 +1,61 @@
+"""A 2-D grid of single-glyph cells.
+
+The grid is the renderer's input surface: callers paint terrain and actors
+into cells, then hand the grid to ``text_renderer`` for framing.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from understone.screen.palette import Color
+
+
+@dataclass(frozen=True, slots=True)
+class Cell:
+    """A single rendered position: exactly one glyph plus a colour role."""
+
+    glyph: str
+    color: Color
+
+    def __post_init__(self) -> None:
+        if len(self.glyph) != 1:
+            raise ValueError(f"cell glyph must be exactly one character, got {self.glyph!r}")
+
+
+_BLANK = Cell(" ", Color.DEFAULT)
+
+
+class CellGrid:
+    """A mutable ``rows`` x ``cols`` grid of cells."""
+
+    def __init__(self, rows: int, cols: int) -> None:
+        if rows <= 0 or cols <= 0:
+            raise ValueError(f"grid must be positive, got {rows}x{cols}")
+        self.rows = rows
+        self.cols = cols
+        self._cells: list[list[Cell]] = [[_BLANK for _ in range(cols)] for _ in range(rows)]
+
+    def blank(self) -> None:
+        """Reset every cell to the blank cell."""
+        for r in range(self.rows):
+            for c in range(self.cols):
+                self._cells[r][c] = _BLANK
+
+    def set(self, r: int, c: int, cell: Cell) -> None:
+        """Paint *cell* at row *r*, column *c* (bounds-checked)."""
+        if not (0 <= r < self.rows and 0 <= c < self.cols):
+            raise IndexError(f"cell ({r},{c}) out of bounds for {self.rows}x{self.cols}")
+        self._cells[r][c] = cell
+
+    def get(self, r: int, c: int) -> Cell:
+        """Return the cell at row *r*, column *c* (bounds-checked)."""
+        if not (0 <= r < self.rows and 0 <= c < self.cols):
+            raise IndexError(f"cell ({r},{c}) out of bounds for {self.rows}x{self.cols}")
+        return self._cells[r][c]
+
+    def row_glyphs(self, r: int) -> str:
+        """Return row *r* as a string of its glyphs."""
+        if not (0 <= r < self.rows):
+            raise IndexError(f"row {r} out of bounds for {self.rows} rows")
+        return "".join(cell.glyph for cell in self._cells[r])

examples/door-game/understone/screen/menus.py

@@ -0,0 +1,47 @@
+"""Classic door-game menu rendering for location interiors.
+
+A menu is a boxed title, a block of flavour/body lines, an option line of
+the ``(B)uy  (S)ell  (L)eave`` form, and a footer status line.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from understone.screen.box import BL, BR, H, V, border_with_title
+
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+
+
+def render_menu(
+    title: str,
+    lines: Sequence[str],
+    options: Sequence[str],
+    status: str,
+) -> str:
+    """Render a boxed location menu.
+
+    *title* is centred in the top border, *lines* form the body (each
+    left-padded inside the box), *options* are joined with two spaces into
+    an option line, and *status* prints under the box.
+    """
+    body = list(lines)
+    option_line = "  ".join(options)
+    if option_line:
+        body.append("")
+        body.append(option_line)
+    inner = _inner_width(title, body)
+    out = [border_with_title(inner, title)]
+    for line in body:
+        out.append(V + " " + line.ljust(inner - 1) + V)
+    out.append(BL + (H * inner) + BR)
+    out.append(status)
+    return "\n".join(out)
+
+
+def _inner_width(title: str, body: Sequence[str]) -> int:
+    """Choose an inner width that fits the title and the widest body line."""
+    title_need = len(title.strip()) + 4
+    body_need = max((len(line) + 2 for line in body), default=0)
+    return max(title_need, body_need, 24)

examples/door-game/understone/screen/palette.py

@@ -0,0 +1,65 @@
+"""Colour vocabulary for cells.
+
+Colours are *stored* on cells and rendered by the live Watch page, which maps
+each role to a hue (see ``watch.PALETTE``). The text frame renderer stays
+monochrome — it emits glyphs only — so a cell's colour rides the grid model
+untouched until a colour-aware renderer (the Watch today, an ANSI terminal
+later) reads it.
+"""
+
+from __future__ import annotations
+
+from enum import Enum
+
+
+class Color(Enum):
+    """Semantic colour roles for grid cells.
+
+    One global vocabulary, shared by every world — there are no per-world or
+    per-theme palettes. Roles are split into two families: the runtime overlay
+    colours an actor or item wears (``PLAYER``/``OTHER_PLAYER``/``MONSTER``/
+    ``ITEM``) and the author-assignable terrain/location roles a pack paints its
+    map with (everything else). A future colour renderer maps each role to a
+    hue; the Watch already does (see ``watch.PALETTE``).
+    """
+
+    DEFAULT = "default"
+    WALL = "wall"
+    FLOOR = "floor"
+    PLAYER = "player"
+    OTHER_PLAYER = "other_player"
+    MONSTER = "monster"
+    ITEM = "item"
+    WATER = "water"
+    TREE = "tree"
+    TOWN = "town"
+    DUNGEON = "dungeon"
+    # Expanded terrain/location roles (v0.9) — so distinct types read by hue and
+    # not only by glyph. ROAD splits paths off FLOOR; FOREST is lush dense
+    # vegetation; SCRUB is its barren counterpart — rough, non-lush dense terrain
+    # (volcanic cinder, desert scrub) that must NOT read as green woods; LAVA
+    # gives molten ground its own orange (no longer mis-sharing WATER's blue);
+    # BARREN gives open wasteland ground a taupe; INN/SHOP/HEALER give each town
+    # building its own hue (TOWN stays as a generic fallback).
+    ROAD = "road"
+    FOREST = "forest"
+    SCRUB = "scrub"
+    LAVA = "lava"
+    BARREN = "barren"
+    INN = "inn"
+    SHOP = "shop"
+    HEALER = "healer"
+
+    @classmethod
+    def assignable(cls) -> list[Color]:
+        """The roles a pack may paint terrain or a location with.
+
+        One source of truth for the overlay-vs-assignable split. Excludes the
+        runtime overlay colours an actor/item wears (``PLAYER``/
+        ``OTHER_PLAYER``/``MONSTER``/``ITEM``) and the ``DEFAULT`` fallback —
+        none of which an author assigns. Consumers (the authoring manual and
+        its test) read this so the documented vocabulary can never drift from
+        the enum. Returned in definition order.
+        """
+        overlay = {cls.DEFAULT, cls.PLAYER, cls.OTHER_PLAYER, cls.MONSTER, cls.ITEM}
+        return [role for role in cls if role not in overlay]

examples/door-game/understone/screen/text_renderer.py

@@ -0,0 +1,32 @@
+"""Frame rendering — wrap a grid in a single box border with a title and status.
+
+Deterministic and glyph-only (no ANSI). The title is centred within the
+top border run; the status line is printed under the closed box.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from understone.screen.box import BL, BR, H, V, border_with_title
+
+if TYPE_CHECKING:
+    from understone.screen.grid import CellGrid
+
+
+def render_frame(grid: CellGrid, *, title: str, status: str) -> str:
+    """Render *grid* inside a box, with *title* in the top border and *status* below.
+
+    The inner width equals the grid's column count. The title is centred
+    in the horizontal run of the top border; if it does not fit it is
+    truncated to the available run.
+    """
+    inner = grid.cols
+    top = border_with_title(inner, title)
+    bottom = BL + (H * inner) + BR
+    lines = [top]
+    for r in range(grid.rows):
+        lines.append(V + grid.row_glyphs(r) + V)
+    lines.append(bottom)
+    lines.append(status)
+    return "\n".join(lines)

examples/door-game/understone/screen/texture.py

@@ -0,0 +1,54 @@
+"""Deterministic terrain texturing — vary a terrain glyph by map position.
+
+A field of identical `.`s reads flat; swapping in an occasional `,` or `'`
+gives the overworld a hand-stippled BBS texture without storing anything on the
+map. The variation is a PURE FUNCTION OF THE CELL COORDINATE, so it is stable
+across redraws (a cell always picks the same variant) and reproducible — the
+model never sees it, only the renderer.
+
+Only *terrain* cells are textured. The player marker, the other-player marker,
+and location glyphs are painted on top and are never varied, so the eye can
+always find them.
+
+LOCKSTEP CONTRACT. The Watch page (``understone.watch.WATCH_HTML``) paints its
+own base map in JavaScript and reproduces the EXACT same selection — the same
+``VARIANTS`` rows and the same ``(x * _HASH_X + y * _HASH_Y) % n`` index. The
+page builds that index string FROM the :data:`_HASH_X` / :data:`_HASH_Y`
+constants here (``understone.watch`` imports them), so a retune of either
+number moves the JS with it; only the ``VARIANTS`` table must still be mirrored
+by hand, or the live map and the tool frames will drift apart.
+"""
+
+from __future__ import annotations
+
+# The position hash multipliers. The variant index for a cell is
+# ``(x * _HASH_X + y * _HASH_Y) % len`` — two odd, coprime constants chosen so
+# neighbouring cells spread across the variant row rather than banding. The
+# Watch JS builds its own copy of this formula FROM these same two numbers
+# (``understone.watch`` imports them), so a retune here moves the page in
+# lockstep; a guard test pins the agreement.
+_HASH_X = 31
+_HASH_Y = 17
+
+# Base glyph -> the ordered string of glyphs it may render as. The base glyph
+# is index 0, so a cell that hashes to 0 is unchanged. Glyphs not listed here
+# are never varied. Keep in lockstep with the Watch JS VARIANTS map.
+VARIANTS: dict[str, str] = {
+    ".": ".,'",
+    "≋": "≋≈",
+}
+
+
+def textured(glyph: str, x: int, y: int) -> str:
+    """Return the variant of *glyph* for cell ``(x, y)``, or *glyph* unchanged.
+
+    When *glyph* has a :data:`VARIANTS` row, the cell coordinate selects one of
+    its variants by ``(x * _HASH_X + y * _HASH_Y) % len`` — a fixed,
+    position-only hash so the choice is stable per cell and identical to the
+    Watch's. Glyphs with no row (every actor and location glyph, and any
+    un-listed terrain) are returned as-is.
+    """
+    choices = VARIANTS.get(glyph)
+    if choices is None:
+        return glyph
+    return choices[(x * _HASH_X + y * _HASH_Y) % len(choices)]

examples/door-game/understone/screen/viewport.py

@@ -0,0 +1,40 @@
+"""Viewport window maths — pure integer arithmetic, no state.
+
+Computes the top-left corner of a view window over a larger map, centred
+on a focus point but clamped to map edges so the window never wraps and
+never runs off the map. At edges the focus point sits off-centre.
+"""
+
+from __future__ import annotations
+
+
+def compute_window(
+    map_w: int,
+    map_h: int,
+    view_w: int,
+    view_h: int,
+    cx: int,
+    cy: int,
+) -> tuple[int, int]:
+    """Return ``(x0, y0)`` top-left map coords for a view centred on ``(cx, cy)``.
+
+    The window is clamped so ``[x0, x0 + view_w)`` stays within
+    ``[0, map_w)`` (and likewise for the vertical axis). When the map is
+    smaller than the view the origin pins to ``0``.
+    """
+    x0 = _clamp_axis(map_w, view_w, cx)
+    y0 = _clamp_axis(map_h, view_h, cy)
+    return x0, y0
+
+
+def _clamp_axis(map_size: int, view_size: int, center: int) -> int:
+    """Clamp one axis: centre on ``center`` then pull inside the map edges."""
+    if view_size >= map_size:
+        return 0
+    origin = center - view_size // 2
+    max_origin = map_size - view_size
+    if origin < 0:
+        return 0
+    if origin > max_origin:
+        return max_origin
+    return origin

examples/door-game/understone/server.py

@@ -0,0 +1,648 @@
+"""MCP server for Understone — the only module that imports ``mcp`` (or ``starlette``).
+
+Nine ``door_*`` tools form the entire player interface. Every handler is a
+synchronous ``def`` that takes and returns ``str``; no exception is allowed
+to cross the MCP boundary (each handler catches, logs server-side, and
+returns an in-fiction line). The handlers are thin wrappers over a single
+module-level :class:`~understone.game.Game`; all rules live behind that
+façade.
+
+Three extra HTTP routes (``/watch`` and its two JSON feeds) serve the
+read-only spectator page from :mod:`understone.watch`. They are registered via
+FastMCP's ``custom_route`` and ride inside the streamable-http app; the
+``starlette`` request/response types appear ONLY here, mirroring the MCP SDK's
+own ``custom_route`` examples. The routes are unauthenticated by design and
+strictly read-only — they never mutate or persist world state.
+
+Usage::
+
+    understone                 # via entry point (stdio transport)
+    python -m understone       # via module
+    understone validate PATH   # check a content pack loads cleanly
+    understone newpack PATH    # scaffold a new pack + authoring manual
+    understone worlds          # list the bundled worlds and their soundness
+
+Environment variables
+---------------------
+UNDERSTONE_DB         SQLite path (default: ./understone.db)
+UNDERSTONE_WORLD      Content-pack directory (default: packaged world/data)
+UNDERSTONE_TRANSPORT  "stdio" (default) or "streamable-http"
+UNDERSTONE_HOST       Bind host for http transport (default: 127.0.0.1)
+UNDERSTONE_PORT       Bind port for http transport (default: 8077)
+UNDERSTONE_PATH       HTTP path for the MCP endpoint (default: /mcp)
+"""
+
+from __future__ import annotations
+
+import argparse
+import logging
+import os
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+from mcp.server.fastmcp import FastMCP
+from mcp.server.transport_security import TransportSecuritySettings
+from starlette.responses import HTMLResponse, JSONResponse, Response
+
+from understone import cli, sim, watch
+from understone.errors import WorldLoadError
+from understone.game import Game
+from understone.persistence import Store
+from understone.world import PACKAGED_WORLD_DIR
+from understone.world.loader import load_world
+
+if TYPE_CHECKING:
+    from starlette.applications import Starlette
+    from starlette.requests import Request
+
+log = logging.getLogger(__name__)
+
+_PREMISE = (
+    "Understone is a shared-world BBS door game played through these tools. "
+    "Call door_help first to learn how to narrate it."
+)
+
+# The DM manual returned by door_help — a module constant so it is stable and
+# greppable. It teaches an assistant how to run the game responsibly.
+_DM_MANUAL = """\
+UNDERSTONE — A GUIDE FOR THE GAME MASTER
+
+WHAT THIS IS
+  Understone is a multiplayer, BBS-style ANSI door game — a small text RPG in
+  the lineage of the classic BBS door games. Many players share ONE
+  persistent world hosted by this server. You are the storyteller at the
+  terminal; the server is the rules engine and the single source of truth.
+
+THE GOLDEN RULE
+  The server is authoritative. Never invent dice rolls, loot, gold, hit
+  points, map tiles, or outcomes. Every number and event comes back from a
+  tool call. Narrate AROUND the facts the tools return — never ahead of them.
+  If you want something to happen, call the tool and see what the world says.
+
+THE TWO MODES OF PLAY
+  1. The overworld (TILE mode). Tools return an ASCII "keyframe": a bordered
+     map window centred on the player. '@' is the player, '☻' is another
+     adventurer, glyphs are buildings (⌂ inn, $ shop, ✚ healer, ∩ dungeon).
+     Movement here is FREE — it costs no daily turns.
+  2. Location interiors (MENU mode). Stepping onto a building opens a menu of
+     options like (R)est, (B)uy, (H)eal, (D)escend, (L)eave.
+
+PRESENTING FRAMES
+  When a tool returns a map or a menu, show it to the player VERBATIM inside a
+  fenced code block so the box-drawing lines stay aligned. Then add your prose
+  underneath. Do not redraw or paraphrase the frame.
+
+NARRATION
+  Be vivid and in-fiction. Turn the terse result lines ("You travel 3 steps.",
+  "+8 XP, +3 gold.") into atmosphere. Keep your additions consistent with the
+  returned facts and the high-fantasy tone of the Vale of Understone.
+
+THE DAILY RHYTHM
+  Each adventurer has a small budget of turns per real-world UTC day. Only
+  fighting, descending, and challenging the Wyrm spend a turn; moving,
+  resting, shopping and looking do not. When the budget is gone, the day is
+  done — encourage the player to return tomorrow. This is a correspondence
+  game: a little each day.
+
+WANDERING THE FOREST (the texture of a walk)
+  A step through wild country may turn up more than a monster. The server
+  rolls a private encounter table as the player walks: most often a foe (which
+  stops the walk for a fight or flight), but sometimes a purse of gold, a
+  healing spring, a small trap (it can never kill — it floors at 1 HP), or a
+  scrap of Vale lore. The non-combat finds are applied at once, narrated in
+  the move result, and do NOT stop the walk; at most one such event happens
+  per move. These finds are PRIVATE — they are not Herald news — so narrate
+  them as the quiet texture of travelling, and watch the lore: it whispers of
+  something coiled beneath the dungeon.
+
+DELVING DEEP (the reasons to come back)
+  Beneath the daily reset are four standing draws that reward a returning hero.
+  * THE RUNG LADDER. The dungeon is a ladder of guardians fought one rung per
+    'descend' (each costs a daily turn). A descent faces the NEXT rung past your
+    deepest; a win advances your depth and you climb back out, a loss bounces
+    you home but your depth PERSISTS — you re-enter where you left off. Reaching
+    the last rung opens the Wyrm's door (the depth gate above). Narrate the deep
+    as a slow, earned descent, a rung at a time.
+  * THE SATCHEL AND THE DEATH-SAVE. A small satchel carries a few potions
+    (buying one at the shop now STOWS it instead of drinking it). 'quaff'
+    (anywhere, no turn) drinks the strongest. The heart of it: if a fight would
+    KILL the active fighter and they carry a potion, the strongest is drunk
+    AUTOMATICALLY — they survive standing at the potion's value, no bounce, no
+    spawn reset. Play that beat big: the elixir burning down their throat at the
+    edge of death. (A sleeping ambush victim never auto-quaffs — they are
+    asleep.)
+  * THE FORGE — GOLD AND ORE. The shop's forge adds a +1 edge to the equipped
+    weapon or armour ('forge' target="weapon"/"armour"), up to a cap, each tier
+    dearer than the last. A step costs gold AND forge ore — a material the hero
+    EARNS in combat, never buys: every cleared dungeon rung drops some, and a won
+    forest fight sometimes turns up a little. So the forge is fed by descending,
+    not just by a fat purse; a hero short of ore is told so. Swapping or selling
+    a forged piece loses the edge with it.
+  * RARE BEASTS. A few named beasts prowl the forest, surfacing seldom. Felling
+    one is loud — a public Herald flash — and it always guards a draught that
+    drops into the satchel (if there is room). Treat a rare kill as a small
+    legend in itself.
+
+THE WYRM BELOW (the endgame, and how to win)
+  Deep under the dungeon sleeps the Wyrm Below — a fixed, fearsome boss and
+  the ONLY win condition. At the dungeon, a sufficiently seasoned hero may
+  'challenge' it (door_action action="challenge"). The Wyrm gates on BOTH
+  level AND depth: an under-level hero is turned away first, and even a high
+  hero who has not plumbed the deep to its floor (see DELVING DEEP) is told the
+  Wyrm will not stir. Once both are met, the challenge spends a daily turn and
+  resolves in one call, like a fight.
+    * On victory the hero FREES THE VALE. The triumph is heralded to everyone,
+      the run is carved into the Hall of Legends (shown by door_rank), and the
+      hero is reborn in a classic-door-game-style legacy reset: level, gold, gear and stats
+      return to first-day values and they stand again at the town — but they
+      keep a permanent ★ for the win, and may set out to do it all again. Their
+      remaining turns for the day and their place in the world carry over.
+    * On defeat the Wyrm devours them; they wake at the spawn, barely alive.
+  Play this beat big: it is the climax of a whole run. Narrate the reset as the
+  Vale renewing itself around an undying legend, not as a death.
+
+BESTOWING FORTUNE (use sparingly)
+  door_bestow lets you, the storyteller, grant a little gold or healing to
+  mark a great story moment — a heroic rescue, a clever solution, a poignant
+  death-defiance. It NEVER grants items (gear comes from the shop) and NEVER
+  grants turns (the clock does not bend). It is capped by a small daily pool
+  per player, and every bestowal is written to the public log for all to see.
+  Treat it as seasoning, not a salt-shaker: reserve it for the rare, earned
+  beat, and never promise a reward you cannot actually deliver within the cap.
+
+THE SOCIAL LAYER (rivals, mail, and dice)
+  Understone is a SHARED world, and three verbs let players touch one another.
+  * AMBUSH (door_action action="ambush" target=<player>, on the overworld).
+    A classic-door-game-style player-kill: you fall upon a RIVAL WHO HAS NOT YET ACTED
+    TODAY and rob them. The SLEEP RULE is the heart of it — a player who has
+    already taken their turn that day is awake and cannot be ambushed, so the
+    surest defence is simply to play. The gatekeeper shields the young (both of
+    you must clear a level floor) and only matches near-equals (a level band).
+    On a win you take a slice of their gold and they wake at the spawn at 1 HP;
+    a public Herald crows the deed and the victim gets a PRIVATE note. But the
+    sleeper may WAKE: lose, and YOU are the one who flees bleeding, shamed on
+    the feed and gaining nothing. You get one attempt per rival per day, win or
+    lose. Narrate ambush as a real betrayal — and losing one as just deserts.
+  * POST (door_action action="post" target=<player> text=<message>, anywhere).
+    Leave a private note at the inn for another player; they read it on their
+    next door_log under "While you were away". It costs no turn, is capped per
+    day, and the note is PRIVATE — it never reaches the public Herald or the
+    lobby TV. Good for taunts after an ambush, alliances, or a kind word.
+  * GAMBLE (door_action action="gamble" amount=<gold>, at the inn).
+    Wager gold on a single throw of 2d6 against the house: roll higher to
+    double your stake, tie to push, roll lower to lose it. It costs no turn but
+    is capped per day. A big win is heralded; a quiet one is just a story you
+    tell. Remind players the house has no mercy and the odds are even at best.
+
+THE VAULT (banking coin at the inn)
+  The inn keeps a strongbox. DEPOSIT (door_action action="deposit" amount=<gold>)
+  moves coin from the hero's hand into the vault; WITHDRAW (action="withdraw"
+  amount=<gold>) draws it back. Neither costs a turn. Two things make the vault
+  matter: banked gold is SAFE FROM AMBUSH (a sleeping-robber lifts only what the
+  victim carries), so banking before logging off is the way to protect a purse;
+  and banked gold SURVIVES THE WYRM-WIN RESET — it is the one wealth a reborn
+  hero keeps, alongside their ★. Suggest a wary player bank their winnings.
+
+TOOL CHEAT-SHEET
+  door_help                      This manual.
+  door_join(player)              Sign in (creates or resumes a character).
+  door_status(player)            Read the character sheet.
+  door_look(player)              Redraw the current view (map or menu).
+  door_move(player, ...)         Walk the overworld (free). steps="NNEE" or
+                                 heading="east" + distance=3 (max 8 per call).
+  door_action(player, action)    Context verb: fight, flee, ambush (a rival),
+                                 rest, deposit/withdraw (the inn vault), buy,
+                                 sell, forge (a +1 edge, gold + ore), heal,
+                                 gamble (dice at the inn), descend (one rung),
+                                 challenge (the Wyrm), post (a note), quaff (a
+                                 carried potion), leave.
+  door_log(player)               Read the Understone Herald (the shared feed).
+  door_rank(player)              The leaderboard + Hall of Legends (★ = wins).
+  door_bestow(player, reason...) Grant a little gold/healing for a story beat.
+
+GETTING STARTED
+  Ask the player their adventurer's name, call door_join, present the opening
+  keyframe, and set the scene: a small town at the western edge of a wooded
+  vale, a road running east toward darker country and a dungeon mouth.
+"""
+
+_BLANK_NAME = 'The gatekeeper squints. "I didn\'t catch your name, traveller."'
+
+# Module-level game singleton, built lazily so tests can inject their own.
+_GAME: Game | None = None
+
+
+def _build_game(watch_url: str | None = None) -> Game:
+    """Construct the module Game from environment configuration."""
+    db_path = os.environ.get("UNDERSTONE_DB", "understone.db")
+    world_dir = os.environ.get("UNDERSTONE_WORLD") or str(PACKAGED_WORLD_DIR)
+    world = load_world(world_dir)
+    store = Store(db_path)
+    return Game(world, store, watch_url=watch_url)
+
+
+def _game() -> Game:
+    """Return the module game, building it on first use."""
+    global _GAME
+    if _GAME is None:
+        _GAME = _build_game()
+    return _GAME
+
+
+def _set_game(game: Game) -> None:
+    """Install a prebuilt game (used by create_app / tests)."""
+    global _GAME
+    _GAME = game
+
+
+def _guard_name(player: str) -> str | None:
+    """Return the blank-name refusal when *player* is empty, else None."""
+    return None if player.strip() else _BLANK_NAME
+
+
+mcp: FastMCP = FastMCP(
+    "understone",
+    instructions=_PREMISE,
+)
+
+
+@mcp.tool()
+def door_help() -> str:
+    """Read the Understone game-master manual — start here.
+
+    Returns a short guide for running this multiplayer, BBS-style ANSI door
+    game (a classic text RPG / dungeon adventure): the two play modes, how
+    to present the ASCII map frames, the daily-turn rhythm, and the full tool
+    cheat-sheet. Call door_help before your first session to learn how to run
+    the game, then call door_join to begin.
+    """
+    watch_line = _game().watch_line()
+    if watch_line:
+        return f"{_DM_MANUAL}\nTHE LOBBY TV\n  {watch_line}\n"
+    return _DM_MANUAL
+
+
+@mcp.tool()
+def door_join(player: str) -> str:
+    """Sign an adventurer into the shared world of Understone — call this first.
+
+    Understone is a multiplayer, BBS-style ANSI door game: a text adventure /
+    dungeon RPG in the spirit of the classic BBS door games, played entirely
+    through these tools. This creates a new character at the town, or resumes
+    an existing one by name, and returns the opening overworld map frame. New
+    to running it? Call door_help before your first session.
+
+    Args:
+        player: The adventurer's name (their identity in the world).
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().join(player)
+    except Exception:
+        log.exception("door_join failed for %r", player)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_status(player: str) -> str:
+    """Show an adventurer's character sheet (level, HP, gear, gold, turns).
+
+    Read-only. Use it to check progress before deciding what to do next.
+
+    Args:
+        player: The adventurer's name.
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().status(player)
+    except Exception:
+        log.exception("door_status failed for %r", player)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_look(player: str) -> str:
+    """Redraw what the adventurer currently sees (read-only).
+
+    On the overworld this is an ASCII map keyframe centred on the player
+    ('@' is you, '☻' are other players, glyphs are buildings). Inside a
+    building it is that location's menu. Present the result verbatim in a
+    fenced code block, then narrate.
+
+    Args:
+        player: The adventurer's name.
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().look(player)
+    except Exception:
+        log.exception("door_look failed for %r", player)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_move(player: str, steps: str = "", heading: str = "", distance: int = 1) -> str:
+    """Walk the overworld — movement is free and never costs a daily turn.
+
+    Only valid on the overworld (in a building, use door_action 'leave'
+    first). Give EITHER a compact ``steps`` string of cardinal letters such
+    as "NNEE", OR a ``heading`` ("north"/"south"/"east"/"west") with a
+    ``distance``. At most 8 cells move per call; the walk stops early at
+    walls, water, a building door, or a wandering monster.
+
+    Args:
+        player: The adventurer's name.
+        steps: Cardinal letters, e.g. "NNEE" (takes precedence if given).
+        heading: A compass direction used with distance.
+        distance: How many cells to travel along heading (1-8).
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().move(player, steps, heading, distance)
+    except Exception:
+        log.exception("door_move failed for %r", player)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_action(
+    player: str,
+    action: str,
+    target: str = "",
+    item: str = "",
+    text: str = "",
+    amount: int = 0,
+) -> str:
+    """Take a context-sensitive action in the world.
+
+    The legal verbs depend on where the adventurer is. On the overworld:
+    'fight' or 'flee' a wandering monster (fighting spends one daily turn), or
+    'ambush' a named rival who has not yet acted today — a sleeping-rival
+    robbery in the spirit of the classic door-game player-kill (target=<name>, spends a turn).
+    Inside a building: 'rest' (inn), 'buy'/'sell'/'forge' (shop), 'heal'
+    (healer), or 'leave'. At the inn you may also 'gamble' a stake of gold at
+    dice (amount=<gold>), or bank coin in the vault with 'deposit'/'withdraw'
+    (amount=<gold>) — banked gold is safe from ambush and survives a Wyrm-win
+    reset. Buying a potion now stows it in your satchel rather than drinking it;
+    'forge' (target="weapon"/"armour", at the shop) spends gold AND forge ore
+    (won in the deep) to add a +1 edge to your equipped gear, up to a cap. At
+    the dungeon:
+    'descend' ONE rung of the deep — the next guardian past your deepest, one
+    per turn — or 'challenge' the Wyrm Below, the endgame boss and the only way
+    to win. Descending a rung advances your depth; reaching the floor opens the
+    Wyrm's door. The challenge is gated by BOTH level and depth (you must have
+    plumbed the deep to its floor) and, once allowed, spends a daily turn and
+    resolves in a single call like a fight: a victory frees the Vale and begins
+    a new life (see door_help), a defeat bounces you home. Anywhere and at no
+    turn cost: 'post' leaves a private note for another player (target=<name>,
+    text=<message>) read on their next door_log, and 'quaff' drinks the
+    strongest potion from your satchel. An illegal verb returns the verbs valid
+    right here.
+
+    Args:
+        player: The adventurer's name.
+        action: The verb to attempt (fight, flee, ambush, rest, deposit,
+            withdraw, buy, sell, forge, heal, gamble, descend, challenge, post,
+            quaff, leave).
+        target: The other player's name for 'ambush'/'post', or the slot
+            ("weapon"/"armour") for 'forge'.
+        item: For shop 'buy', the item id to purchase.
+        text: For 'post', the note left for the target (<= 120 characters).
+        amount: For inn 'gamble', the gold wagered on the dice; for the vault
+            'deposit'/'withdraw', the gold moved.
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().action(player, action, target, item, text, amount)
+    except Exception:
+        log.exception("door_action failed for %r action=%r", player, action)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_log(player: str) -> str:
+    """Catch up on what happened in the shared world while the player was away.
+
+    Returns the events since this adventurer last checked (fights, deaths,
+    blessings, descents by anyone) and advances their personal marker.
+
+    Args:
+        player: The adventurer's name.
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().log(player)
+    except Exception:
+        log.exception("door_log failed for %r", player)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_rank(player: str = "") -> str:
+    """Show the Roll of Heroes — the top-ten leaderboard.
+
+    Ordered by level, then experience, then name. If the caller names
+    themselves and they place in the top ten, their row is marked. Each ★
+    beside a name is one slaying of the Wyrm Below. Below the table, the Hall
+    of Legends lists the most recent completed runs (name, level at the kill,
+    days the run took, date); it is omitted while no one has yet won.
+
+    Args:
+        player: The caller's name (optional; marks their row when present).
+    """
+    try:
+        return _game().rank(player)
+    except Exception:
+        log.exception("door_rank failed for %r", player)
+        return _unexpected()
+
+
+@mcp.tool()
+def door_bestow(player: str, reason: str, gold: int = 0, heal: int = 0) -> str:
+    """Grant a small gift of gold or healing to mark a great story moment.
+
+    This is the game master's discretionary channel, to be used SPARINGLY for
+    earned, story-driven beats. It grants only gold and/or healing — never
+    items (gear comes from the shop) and never turns (the daily clock does not
+    bend). Each grant is capped by a small daily pool per adventurer and is
+    written to the public log, so spend it on the rare moment that deserves
+    it; do not promise more than the cap allows. When a pack sets healing to
+    cost nothing, a bestowed heal is free and draws nothing from the pool.
+
+    Args:
+        player: The adventurer receiving the gift.
+        reason: A short, in-fiction reason (<= 120 characters).
+        gold: Gold to grant (>= 0).
+        heal: HP to restore (>= 0); only the missing portion is applied and
+            charged against the pool.
+    """
+    blank = _guard_name(player)
+    if blank is not None:
+        return blank
+    try:
+        return _game().bestow(player, reason, gold, heal)
+    except Exception:
+        log.exception("door_bestow failed for %r", player)
+        return _unexpected()
+
+
+# FastMCP.custom_route has no return annotation upstream (mcp 1.27.2), so mypy
+# reads the decorator as untyped; the ignore is scoped to that single gap.
+@mcp.custom_route("/watch", methods=["GET"])  # type: ignore[untyped-decorator]
+async def watch_page(_request: Request) -> Response:
+    """Serve the read-only CRT spectator page (static HTML, no world reads)."""
+    return HTMLResponse(watch.WATCH_HTML)
+
+
+@mcp.custom_route("/watch/world.json", methods=["GET"])  # type: ignore[untyped-decorator]
+async def watch_world(_request: Request) -> Response:
+    """Serve the STATIC map payload (dimensions, coloured rows, locations)."""
+    return JSONResponse(watch.build_world_payload(_game().world))
+
+
+@mcp.custom_route("/watch/state.json", methods=["GET"])  # type: ignore[untyped-decorator]
+async def watch_state(_request: Request) -> Response:
+    """Serve the DYNAMIC snapshot (players, Herald, Hall) — read-only.
+
+    The builder reads the module Game with no ``await`` in between, so each
+    response is a consistent point-in-time snapshot of the shared world.
+    """
+    return JSONResponse(watch.build_state_payload(_game()))
+
+
+def _unexpected() -> str:
+    """In-fiction line for an unexpected server-side error."""
+    return (
+        "A strange fog rolls through the Vale and the moment slips away. "
+        "(Something went wrong; try again.)"
+    )
+
+
+def create_app(
+    db_path: str, world_dir: str | None = None, watch_url: str | None = None
+) -> Starlette:
+    """Build the streamable-HTTP ASGI app backed by a fresh game.
+
+    Used by both ``main`` (for the http transport) and the integration tests,
+    so tests can point at a temp DB without environment juggling. ``watch_url``,
+    when given, is the spectator page URL the join banner and help manual
+    advertise; ``main`` derives it from the bind host/port.
+    """
+    world = load_world(world_dir or str(PACKAGED_WORLD_DIR))
+    store = Store(db_path)
+    _set_game(Game(world, store, watch_url=watch_url))
+    return mcp.streamable_http_app()
+
+
+def _serve() -> None:
+    """Serve the Understone MCP world over the configured transport.
+
+    Honours UNDERSTONE_TRANSPORT: "stdio" (default) or "streamable-http".
+    For http, host/port/path are read from the environment and applied to the
+    FastMCP settings before serving. This is the actual transport launch; it is
+    kept separate from argument parsing so the parse step has no side effects.
+    """
+    logging.basicConfig(level=logging.INFO)
+    transport = os.environ.get("UNDERSTONE_TRANSPORT", "stdio")
+
+    if transport == "streamable-http":
+        host = os.environ.get("UNDERSTONE_HOST", "127.0.0.1")
+        port = int(os.environ.get("UNDERSTONE_PORT", "8077"))
+        mcp.settings.host = host
+        mcp.settings.port = port
+        mcp.settings.streamable_http_path = os.environ.get("UNDERSTONE_PATH", "/mcp")
+        mcp.settings.stateless_http = False
+        # FastMCP freezes DNS-rebinding protection (a localhost-only Host
+        # allowlist) at CONSTRUCTION, and this module builds `mcp` at import
+        # with the default 127.0.0.1 host — so a 0.0.0.0/LAN bind would 421
+        # "Invalid Host" on /mcp for every remote node (the multi-node case).
+        # Binding off localhost means we intend to accept other hosts, so drop
+        # the allowlist here (matching the SDK's own default for a non-localhost
+        # bind). These routes are unauthenticated by design — serve only on a
+        # trusted network. UNDERSTONE_HOST controls the bind.
+        if host not in ("127.0.0.1", "localhost", "::1"):
+            mcp.settings.transport_security = TransportSecuritySettings(
+                enable_dns_rebinding_protection=False
+            )
+        # The spectator page is only reachable over http, so its URL is composed
+        # here from the bind address. A 0.0.0.0 bind should advertise a host a
+        # browser can actually reach (see the README Watch section).
+        watch_url = f"http://{host}:{port}/watch"
+        # Build the game eagerly (with the watch URL) so a config error surfaces
+        # before serving and the join/help advertisements carry the page link.
+        try:
+            _set_game(_build_game(watch_url))
+        except WorldLoadError as exc:
+            raise SystemExit(f"failed to load world: {exc}") from exc
+        mcp.run(transport="streamable-http")
+        return
+
+    try:
+        _game()
+    except WorldLoadError as exc:
+        raise SystemExit(f"failed to load world: {exc}") from exc
+    mcp.run(transport="stdio")
+
+
+def _build_parser() -> argparse.ArgumentParser:
+    """Build the ``understone`` argument parser: serve (default), validate, newpack.
+
+    Parsing is deliberately free of side effects — no world load, no port bind —
+    so the resolved subcommand can be inspected without serving anything.
+    """
+    parser = argparse.ArgumentParser(
+        prog="understone",
+        description=(
+            "Understone — a BBS-style ANSI door game served over MCP, plus the "
+            "tools to author its world packs."
+        ),
+    )
+    sub = parser.add_subparsers(dest="cmd")
+    sub.add_parser("serve", help="serve the MCP world (the default with no command)")
+    validate = sub.add_parser("validate", help="validate a content pack and print a report")
+    validate.add_argument("path", type=Path, help="the pack directory to validate")
+    newpack = sub.add_parser("newpack", help="scaffold a new content pack from the bundled world")
+    newpack.add_argument("path", type=Path, help="the directory to create the pack in")
+    sub.add_parser("worlds", help="list the bundled worlds and whether each is sound")
+    sim = sub.add_parser("simulate", help="run a greedy balance bot over a pack and report")
+    sim.add_argument("path", type=Path, help="the pack directory to simulate")
+    sim.add_argument("--days", type=int, default=30, help="sim-days to play (default 30)")
+    sim.add_argument("--seed", type=int, default=1, help="RNG seed (default 1)")
+    sim.add_argument(
+        "--seeds",
+        type=int,
+        default=None,
+        help="run a sweep of this many seeds from --seed and aggregate",
+    )
+    return parser
+
+
+def main(argv: list[str] | None = None) -> None:
+    """Run the Understone command line: serve, or author a world pack.
+
+    With no arguments (the entry point and ``python -m understone``) this serves
+    the MCP world exactly as before. ``validate PATH`` and ``newpack PATH`` drive
+    the pack-authoring loop and exit with the verb's status code.
+    """
+    args = _build_parser().parse_args(argv)
+    if args.cmd == "validate":
+        raise SystemExit(cli.cli_validate(args.path))
+    if args.cmd == "newpack":
+        raise SystemExit(cli.cli_newpack(args.path))
+    if args.cmd == "worlds":
+        raise SystemExit(cli.cli_worlds())
+    if args.cmd == "simulate":
+        raise SystemExit(sim.cli_simulate(args.path, args.days, args.seed, seeds=args.seeds))
+    _serve()

examples/door-game/understone/watch.py

@@ -0,0 +1,745 @@
+"""The Watch page — a read-only CRT spectator view of the shared world.
+
+This module is PURE: it imports nothing from ``mcp`` or ``starlette``. It owns
+two payload builders and one self-contained HTML page; the server wires them to
+HTTP routes. Input never flows through here — the Watch is the lobby TV, not a
+controller.
+
+* :func:`build_world_payload` — the STATIC map: dimensions, the legend-coloured
+  terrain rows, and the placed locations. Fetched once by the page.
+* :func:`build_state_payload` — the DYNAMIC snapshot: every player's position
+  and vitals, the recent Herald feed, and the Hall of Legends. Polled.
+* :data:`WATCH_HTML` — one inline-everything page (vanilla JS, phosphor CRT
+  styling) that paints the base map once and overlays the players each poll.
+
+A correspondence game leaves every adventurer on the board between their turns,
+so the state payload reports *all* players, not just the active ones.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from understone.engine.models import Mode
+from understone.engine.satchel import decode_satchel
+from understone.screen import texture
+
+if TYPE_CHECKING:
+    from understone.engine.log import Event
+    from understone.engine.world import World
+    from understone.game import Game
+
+# How many of the newest Herald events the Watch shows, oldest-first.
+_HERALD_LIMIT = 15
+# How many Hall-of-Legends runs the Watch shows.
+_HALL_LIMIT = 5
+
+
+def build_world_payload(world: World) -> dict[str, object]:
+    """Return the STATIC map payload the Watch page fetches once.
+
+    ``glyph_rows`` is the base terrain rendered glyph-for-glyph (locations are
+    NOT burned in here — they ride in ``locations`` so the client can colour
+    them as an overlay). ``legend`` maps every terrain glyph that appears to a
+    palette colour *name*; the client owns the name→hex mapping. Completeness is
+    a contract: every glyph in ``glyph_rows`` has a ``legend`` entry.
+
+    ``theme`` is the pack's Watch CRT palette (``settings.watch_theme``); the
+    page looks it up in its own JS THEME table on fetch and swaps the CSS
+    custom-property values, so each world has its own phosphor colour.
+    """
+    glyph_rows: list[str] = []
+    legend: dict[str, str] = {}
+    for y in range(world.height):
+        chars: list[str] = []
+        for x in range(world.width):
+            terrain = world.terrain_at(x, y)
+            chars.append(terrain.glyph)
+            legend.setdefault(terrain.glyph, terrain.color)
+        glyph_rows.append("".join(chars))
+
+    locations = [
+        {
+            "x": loc.x,
+            "y": loc.y,
+            "glyph": loc.glyph,
+            "name": loc.name,
+            "color": loc.color,
+        }
+        for loc in world.locations
+    ]
+    return {
+        "name": world.name,
+        "width": world.width,
+        "height": world.height,
+        "theme": world.settings.watch_theme,
+        "glyph_rows": glyph_rows,
+        "legend": legend,
+        "locations": locations,
+    }
+
+
+def build_state_payload(game: Game) -> dict[str, object]:
+    """Return the DYNAMIC snapshot payload the Watch page polls.
+
+    Reports every player (a correspondence game keeps idle pieces on the
+    board), the last :data:`_HERALD_LIMIT` events oldest-first, and the top
+    :data:`_HALL_LIMIT` completed runs. ``ts`` is the game clock, so a seeded
+    test clock drives a deterministic payload.
+    """
+    players = [
+        {
+            "name": p.name,
+            "x": p.x,
+            "y": p.y,
+            "level": p.level,
+            "wins": p.wins,
+            "hp": p.hp,
+            "max_hp": p.max_hp,
+            "mode": p.mode.value if isinstance(p.mode, Mode) else str(p.mode),
+            "gold": p.gold,
+            "banked": p.banked,
+            "satchel": _satchel_entries(game, p.satchel),
+        }
+        for p in game.players.values()
+    ]
+    herald = [
+        {"ts": event.ts, "kind": event.kind, "text": event.text} for event in _recent_events(game)
+    ]
+    hall = [
+        {
+            "name": entry.name,
+            "level_at_win": entry.level_at_win,
+            "run_days": entry.run_days,
+            "win_ts": entry.win_ts,
+        }
+        for entry in game.store.top_hall(_HALL_LIMIT)
+    ]
+    return {
+        "ts": game.clock().isoformat(),
+        "players": players,
+        "herald": herald,
+        "hall": hall,
+    }
+
+
+def _satchel_entries(game: Game, satchel: str) -> list[dict[str, object]]:
+    """Decode a player's ``"id:qty"`` satchel into ``[{"name", "qty"}, ...]``.
+
+    Decodes the bag through the shared
+    :func:`~understone.engine.satchel.decode_satchel` codec, then resolves each
+    stack's id to its display name via the world's item table; an id no longer in
+    the pack (a save edited out from under it) falls back to the raw id, so the
+    lobby TV never shows a blank entry. The Watch is read-only, so it only
+    decodes — the name-resolution is the only work that lives here.
+    """
+    entries: list[dict[str, object]] = []
+    for item_id, qty in decode_satchel(satchel):
+        item = game.world.item_by_id(item_id)
+        entries.append({"name": item.name if item is not None else item_id, "qty": qty})
+    return entries
+
+
+def _recent_events(game: Game) -> list[Event]:
+    """Return the last :data:`_HERALD_LIMIT` resident PUBLIC events, oldest-first.
+
+    PRIVATE notes (a non-empty ``target`` — ambush victim alerts, inn mail)
+    are filtered out first: the lobby TV is a public broadsheet and must never
+    show a message addressed to one player. The façade keeps events in
+    ascending id order, so the tail of the public slice IS the newest public
+    window — correct even when AUTOINCREMENT ids are sparse.
+    """
+    public = [event for event in game.events if not event.target]
+    return public[-_HERALD_LIMIT:]
+
+
+# The Watch page. One self-contained document: inline CSS + vanilla JS, no
+# external assets, no innerHTML-with-data (every dynamic node is built with
+# createElement / textContent). The base map is painted once from world.json;
+# players are an absolutely-positioned overlay repainted from state.json every
+# two seconds. On a fetch failure the page dims and shows "SIGNAL LOST".
+#
+# ``__HASH_EXPR__`` is filled below from the texture-module hash constants, so
+# the JS index formula tracks a Python-side retune (see _build_watch_html).
+_WATCH_HTML_TEMPLATE = """\
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>Understone — Live Watch</title>
+<style>
+  :root {
+    --phosphor: #7dffa0;
+    --phosphor-dim: #2f7a46;
+    --amber: #ffb44d;
+    --bg: #050a06;
+    --panel: #0a140d;
+    --edge: #163a22;
+  }
+  * { box-sizing: border-box; }
+  html, body {
+    margin: 0;
+    background: var(--bg);
+    color: var(--phosphor);
+    font-family: "Noto Sans Mono", "DejaVu Sans Mono", "Liberation Mono", "Courier New", monospace;
+    font-size: 14px;
+    line-height: 1.2;
+  }
+  body::after {
+    /* Scanline overlay — faint, non-interactive. */
+    content: "";
+    position: fixed;
+    inset: 0;
+    pointer-events: none;
+    background: repeating-linear-gradient(
+      to bottom,
+      rgba(0, 0, 0, 0) 0px,
+      rgba(0, 0, 0, 0) 2px,
+      rgba(0, 0, 0, 0.22) 3px,
+      rgba(0, 0, 0, 0) 4px
+    );
+    z-index: 50;
+  }
+  body.lost { filter: grayscale(0.7) brightness(0.55); }
+  header {
+    padding: 10px 16px;
+    border-bottom: 1px solid var(--edge);
+    display: flex;
+    align-items: baseline;
+    justify-content: space-between;
+    flex-wrap: wrap;
+    gap: 8px;
+    text-shadow: 0 0 6px rgba(125, 255, 160, 0.5);
+  }
+  header h1 {
+    margin: 0;
+    font-size: 18px;
+    letter-spacing: 2px;
+    text-transform: uppercase;
+  }
+  .live {
+    color: var(--amber);
+    font-size: 13px;
+    letter-spacing: 1px;
+    text-shadow: 0 0 6px rgba(255, 180, 77, 0.5);
+  }
+  .live .dot {
+    display: inline-block;
+    width: 8px;
+    height: 8px;
+    margin-right: 6px;
+    border-radius: 50%;
+    background: var(--amber);
+    box-shadow: 0 0 8px var(--amber);
+    animation: pulse 2s ease-in-out infinite;
+  }
+  body.lost .live .dot { animation: none; background: var(--phosphor-dim); box-shadow: none; }
+  @keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.35; } }
+  main {
+    display: flex;
+    gap: 16px;
+    padding: 16px;
+    align-items: flex-start;
+    flex-wrap: wrap;
+  }
+  .map-frame {
+    position: relative;
+    border: 1px solid var(--edge);
+    background: var(--panel);
+    padding: 8px;
+    overflow: auto;
+    max-width: 100%;
+    box-shadow: inset 0 0 24px rgba(0, 0, 0, 0.6);
+    transition: filter 1.2s ease;
+  }
+  /* Time-of-day wash, toggled from the UTC hour of the state payload. The
+     overlay is non-interactive and sits above the map but below the scanlines.
+     night: a subtle blue dim; dawn/dusk: a faint amber wash; day: nothing. */
+  .map-frame::after {
+    content: "";
+    position: absolute;
+    inset: 0;
+    pointer-events: none;
+    opacity: 0;
+    transition: opacity 1.2s ease, background-color 1.2s ease;
+    z-index: 5;
+  }
+  .map-frame.night { filter: brightness(0.78) saturate(0.85); }
+  .map-frame.night::after { opacity: 1; background-color: rgba(74, 120, 200, 0.16); }
+  .map-frame.twilight::after { opacity: 1; background-color: rgba(255, 180, 77, 0.12); }
+  #map {
+    position: relative;
+    white-space: pre;
+    text-shadow: 0 0 4px rgba(125, 255, 160, 0.35);
+  }
+  #map .row { display: block; }
+  #overlay {
+    position: absolute;
+    top: 0;
+    left: 0;
+    pointer-events: none;
+  }
+  #overlay .pc {
+    position: absolute;
+    color: var(--amber);
+    text-shadow: 0 0 6px rgba(255, 180, 77, 0.8);
+  }
+  aside {
+    flex: 1 1 280px;
+    min-width: 260px;
+    display: flex;
+    flex-direction: column;
+    gap: 16px;
+  }
+  .card {
+    border: 1px solid var(--edge);
+    background: var(--panel);
+    padding: 10px 12px;
+  }
+  .card h2 {
+    margin: 0 0 8px;
+    font-size: 13px;
+    letter-spacing: 1.5px;
+    text-transform: uppercase;
+    color: var(--phosphor);
+    border-bottom: 1px solid var(--edge);
+    padding-bottom: 4px;
+  }
+  ul { margin: 0; padding: 0; list-style: none; }
+  li { padding: 2px 0; }
+  .muted { color: var(--phosphor-dim); }
+  .subline { font-size: 12px; padding-left: 2px; }
+  .adv-name { color: var(--amber); }
+  .stars { color: var(--amber); letter-spacing: 1px; }
+  .feed li { border-bottom: 1px dotted var(--edge); padding: 4px 0; }
+  .feed li:last-child { border-bottom: none; }
+  .feed .ts { color: var(--phosphor-dim); margin-right: 6px; }
+</style>
+</head>
+<body>
+  <header>
+    <h1 id="world-name">The Understone Watch</h1>
+    <div class="live"><span class="dot"></span><span id="live-label">CONNECTING…</span></div>
+  </header>
+  <main>
+    <div class="map-frame">
+      <div id="map"><div id="overlay"></div></div>
+    </div>
+    <aside>
+      <section class="card">
+        <h2>Adventurers</h2>
+        <ul id="adventurers"><li class="muted">…</li></ul>
+      </section>
+      <section class="card">
+        <h2>Hall of Legends</h2>
+        <ul id="hall"><li class="muted">No legends yet.</li></ul>
+      </section>
+      <section class="card">
+        <h2>The Understone Herald</h2>
+        <ul id="herald" class="feed"><li class="muted">…</li></ul>
+      </section>
+    </aside>
+  </main>
+<script>
+(function () {
+  "use strict";
+
+  // Per-world CRT palette. Each named theme is a set of CSS custom-property
+  // values applied to :root when world.json arrives (the pack's
+  // settings.watch_theme picks one). "phosphor" holds the EXACT values of the
+  // :root block above, so the default Vale is pixel-for-pixel unchanged; the
+  // others re-tint the whole console:
+  //   phosphor — the original green CRT (default).
+  //   amber    — a warm gold CRT (classic amber monochrome monitor).
+  //   ice      — a pale, cold blue CRT.
+  //   ember    — a hot red/orange CRT.
+  // The day/night wash from v0.6 composes ON TOP of whichever theme is set.
+  var THEMES = {
+    phosphor: {
+      "--phosphor": "#7dffa0",
+      "--phosphor-dim": "#2f7a46",
+      "--amber": "#ffb44d",
+      "--bg": "#050a06",
+      "--panel": "#0a140d",
+      "--edge": "#163a22"
+    },
+    amber: {
+      "--phosphor": "#ffc14d",
+      "--phosphor-dim": "#7a5320",
+      "--amber": "#fff0a8",
+      "--bg": "#0a0702",
+      "--panel": "#14100a",
+      "--edge": "#3a2c16"
+    },
+    ice: {
+      "--phosphor": "#9fe6ff",
+      "--phosphor-dim": "#2f5f7a",
+      "--amber": "#ffe07d",
+      "--bg": "#04080a",
+      "--panel": "#0a1014",
+      "--edge": "#16303a"
+    },
+    ember: {
+      "--phosphor": "#ff8a6b",
+      "--phosphor-dim": "#7a3320",
+      "--amber": "#ffd07d",
+      "--bg": "#0a0503",
+      "--panel": "#140a07",
+      "--edge": "#3a1c16"
+    }
+  };
+
+  // Swap the CSS custom-property values for the pack's theme. Unknown or
+  // missing theme names fall back to "phosphor", so the console always has a
+  // coherent palette even if a future theme reaches the page unknown.
+  function applyTheme(name) {
+    var theme = THEMES[name] || THEMES.phosphor;
+    for (var prop in theme) {
+      if (Object.prototype.hasOwnProperty.call(theme, prop)) {
+        document.documentElement.style.setProperty(prop, theme[prop]);
+      }
+    }
+  }
+
+  // Palette colour-name -> phosphor-tinted hex. ONE global map, shared by every
+  // world (no per-world or per-theme palettes). Mirrors understone.screen.palette
+  // Color values 1:1 — a guard test asserts every Color role has an entry here,
+  // so a shipped role can never silently fall back to default. The base map is
+  // coloured from this, never from the server.
+  var PALETTE = {
+    default: "#7dffa0",
+    wall: "#5a6b60",
+    floor: "#3f7a52",
+    player: "#ffb44d",
+    other_player: "#ffd089",
+    monster: "#ff6b6b",
+    item: "#ffe07d",
+    water: "#4aa6c8",
+    tree: "#3fae6a",
+    town: "#ffd089",
+    dungeon: "#c98bff",
+    // v0.9 expanded terrain/location roles, chosen for hue separation:
+    road: "#b89a6a",
+    forest: "#6a9f3f",
+    scrub: "#9c6038",
+    lava: "#ff7a3c",
+    barren: "#9a8b7a",
+    inn: "#ff9d4d",
+    shop: "#ffd24d",
+    healer: "#5fd6b0"
+  };
+
+  function colorFor(name) {
+    return PALETTE[name] || PALETTE.default;
+  }
+
+  // Deterministic terrain texture. MUST stay in lockstep with
+  // understone.screen.texture: the same base->variants rows and the same
+  // index formula. The formula below is INTERPOLATED from texture._HASH_X /
+  // _HASH_Y at module build time, so a Python-side retune rewrites this line;
+  // only the VARIANTS rows must still be mirrored by hand.
+  var VARIANTS = {
+    ".": ".,'",
+    "\\u224b": "\\u224b\\u2248"
+  };
+
+  function textured(ch, x, y) {
+    var choices = VARIANTS[ch];
+    if (!choices) { return ch; }
+    return choices.charAt((__HASH_EXPR__) % choices.length);
+  }
+
+  var overlay = document.getElementById("overlay");
+  var mapEl = document.getElementById("map");
+  var liveLabel = document.getElementById("live-label");
+  var dims = null; // {width, height} once the map is painted.
+
+  function pad2(n) { return (n < 10 ? "0" : "") + n; }
+
+  function clockLabel(iso) {
+    var d = new Date(iso);
+    if (isNaN(d.getTime())) { return "--:--:--"; }
+    return pad2(d.getHours()) + ":" + pad2(d.getMinutes()) + ":" + pad2(d.getSeconds());
+  }
+
+  function stars(wins) {
+    if (wins <= 0) { return ""; }
+    if (wins <= 5) { return "\\u2605".repeat(wins); }
+    return "\\u2605x" + wins;
+  }
+
+  // Paint the base map ONCE. Each row is a sequence of <span> runs, a new run
+  // only where the legend colour changes, so a row is a handful of spans.
+  function paintMap(world) {
+    applyTheme(world.theme);
+    document.getElementById("world-name").textContent = world.name + " — Live Watch";
+    var legend = world.legend || {};
+    var rows = world.glyph_rows || [];
+    for (var y = 0; y < rows.length; y++) {
+      var row = rows[y];
+      var rowEl = document.createElement("div");
+      rowEl.className = "row";
+      var runText = "";
+      var runColor = null;
+      for (var x = 0; x < row.length; x++) {
+        var ch = row.charAt(x);
+        // Colour keys off the BASE terrain glyph; the rendered glyph is the
+        // position-keyed variant (a variant shares its terrain's colour).
+        var col = colorFor(legend[ch]);
+        if (runColor === null) { runColor = col; }
+        if (col !== runColor) {
+          rowEl.appendChild(makeSpan(runText, runColor));
+          runText = "";
+          runColor = col;
+        }
+        runText += textured(ch, x, y);
+      }
+      if (runText.length) { rowEl.appendChild(makeSpan(runText, runColor)); }
+      mapEl.insertBefore(rowEl, overlay);
+    }
+    dims = { width: world.width, height: world.height };
+    paintLocations(world.locations || []);
+  }
+
+  function makeSpan(text, color) {
+    var span = document.createElement("span");
+    span.style.color = color;
+    span.textContent = text;
+    return span;
+  }
+
+  // Locations are painted into the overlay layer (above the base terrain) so
+  // their glyph and colour win over the terrain beneath the door.
+  function paintLocations(locations) {
+    for (var i = 0; i < locations.length; i++) {
+      var loc = locations[i];
+      var el = document.createElement("span");
+      el.className = "pc";
+      el.style.left = "calc(" + loc.x + " * 1ch)";
+      el.style.top = "calc(" + loc.y + " * 1lh)";
+      el.style.color = colorFor(loc.color);
+      el.style.textShadow = "0 0 6px " + colorFor(loc.color);
+      el.textContent = loc.glyph;
+      el.title = loc.name;
+      overlay.appendChild(el);
+    }
+  }
+
+  // Player markers live in their own layer, cleared and repainted each poll.
+  var pcLayer = document.createElement("div");
+  pcLayer.id = "pc-layer";
+  overlay.appendChild(pcLayer);
+
+  function paintPlayers(players) {
+    while (pcLayer.firstChild) { pcLayer.removeChild(pcLayer.firstChild); }
+    for (var i = 0; i < players.length; i++) {
+      var p = players[i];
+      var el = document.createElement("span");
+      el.className = "pc";
+      el.style.left = "calc(" + p.x + " * 1ch)";
+      el.style.top = "calc(" + p.y + " * 1lh)";
+      // Every adventurer on the lobby TV is "another player" (there is no
+      // viewer here), so all wear the other-player marker. Mirrors the '☻'
+      // the game frame paints for rivals.
+      el.textContent = "\\u263b";
+      el.title = p.name;
+      pcLayer.appendChild(el);
+    }
+  }
+
+  function renderAdventurers(players) {
+    var list = document.getElementById("adventurers");
+    while (list.firstChild) { list.removeChild(list.firstChild); }
+    if (!players.length) {
+      list.appendChild(muted("The Vale is empty."));
+      return;
+    }
+    var sorted = players.slice().sort(function (a, b) {
+      return b.level - a.level || a.name.localeCompare(b.name);
+    });
+    for (var i = 0; i < sorted.length; i++) {
+      var p = sorted[i];
+      var li = document.createElement("li");
+      var name = document.createElement("span");
+      name.className = "adv-name";
+      name.textContent = p.name;
+      li.appendChild(name);
+      var star = stars(p.wins);
+      if (star) {
+        var s = document.createElement("span");
+        s.className = "stars";
+        s.textContent = " " + star;
+        li.appendChild(s);
+      }
+      var rest = document.createElement("span");
+      rest.className = "muted";
+      rest.textContent = "  Lv" + p.level + "  HP " + p.hp + "/" + p.max_hp;
+      li.appendChild(rest);
+      // A dim sub-line: gold on hand and (if any) gold in the vault. The whole
+      // shared world is on the lobby TV, so every hero's purse is public here.
+      var gold = document.createElement("div");
+      gold.className = "muted subline";
+      var goldText = (p.gold || 0) + "g";
+      if (p.banked) { goldText += "  +" + p.banked + " vault"; }
+      gold.textContent = goldText;
+      li.appendChild(gold);
+      // A second dim sub-line: the satchel stacks ("Name ×qty"), or empty.
+      var sat = document.createElement("div");
+      sat.className = "muted subline";
+      sat.textContent = satchelText(p.satchel || []);
+      li.appendChild(sat);
+      list.appendChild(li);
+    }
+  }
+
+  // Render the satchel stacks as a compact dot-joined line, or an empty note.
+  function satchelText(stacks) {
+    if (!stacks.length) { return "satchel empty"; }
+    var parts = [];
+    for (var i = 0; i < stacks.length; i++) {
+      parts.push(stacks[i].name + " \\u00d7" + stacks[i].qty);
+    }
+    return parts.join(" \\u00b7 ");
+  }
+
+  function renderHall(hall) {
+    var list = document.getElementById("hall");
+    while (list.firstChild) { list.removeChild(list.firstChild); }
+    if (!hall.length) {
+      list.appendChild(muted("No legends yet."));
+      return;
+    }
+    for (var i = 0; i < hall.length; i++) {
+      var h = hall[i];
+      var li = document.createElement("li");
+      var star = document.createElement("span");
+      star.className = "stars";
+      star.textContent = "\\u2605 ";
+      li.appendChild(star);
+      var name = document.createElement("span");
+      name.className = "adv-name";
+      name.textContent = h.name;
+      li.appendChild(name);
+      var rest = document.createElement("span");
+      rest.className = "muted";
+      rest.textContent = "  Lv" + h.level_at_win + "  " + h.run_days + "d  " + (h.win_ts || "").slice(0, 10);
+      li.appendChild(rest);
+      list.appendChild(li);
+    }
+  }
+
+  function renderHerald(herald) {
+    var list = document.getElementById("herald");
+    while (list.firstChild) { list.removeChild(list.firstChild); }
+    if (!herald.length) {
+      list.appendChild(muted("The Vale is still."));
+      return;
+    }
+    for (var i = 0; i < herald.length; i++) {
+      var e = herald[i];
+      var li = document.createElement("li");
+      var ts = document.createElement("span");
+      ts.className = "ts";
+      ts.textContent = clockLabel(e.ts);
+      li.appendChild(ts);
+      var text = document.createElement("span");
+      text.textContent = e.text;
+      li.appendChild(text);
+      list.appendChild(li);
+    }
+  }
+
+  function muted(text) {
+    var li = document.createElement("li");
+    li.className = "muted";
+    li.textContent = text;
+    return li;
+  }
+
+  function setLive(connected, iso) {
+    if (connected) {
+      document.body.classList.remove("lost");
+      liveLabel.textContent = "LIVE \\u2022 updated " + clockLabel(iso);
+    } else {
+      document.body.classList.add("lost");
+      liveLabel.textContent = "SIGNAL LOST";
+    }
+  }
+
+  var mapFrame = document.querySelector(".map-frame");
+
+  // Tint the map by the UTC hour of the world clock. The bands:
+  //   night    20:00-05:59  -> subtle dim + blue ('night' class)
+  //   dawn     06:00-07:59  -> faint amber wash ('twilight' class)
+  //   dusk     18:00-19:59  -> faint amber wash ('twilight' class)
+  //   day      08:00-17:59  -> no tint
+  // UTC (not local) so every spectator sees the same sky as the game clock.
+  function applyDayPhase(iso) {
+    var d = new Date(iso);
+    mapFrame.classList.remove("night", "twilight");
+    if (isNaN(d.getTime())) { return; }
+    var h = d.getUTCHours();
+    if (h >= 20 || h < 6) {
+      mapFrame.classList.add("night");
+    } else if (h < 8 || h >= 18) {
+      mapFrame.classList.add("twilight");
+    }
+  }
+
+  function getJSON(url) {
+    return fetch(url, { cache: "no-store" }).then(function (r) {
+      if (!r.ok) { throw new Error("HTTP " + r.status); }
+      return r.json();
+    });
+  }
+
+  function poll() {
+    getJSON("./watch/state.json").then(function (state) {
+      paintPlayers(state.players || []);
+      renderAdventurers(state.players || []);
+      renderHall(state.hall || []);
+      renderHerald(state.herald || []);
+      applyDayPhase(state.ts);
+      setLive(true, state.ts);
+    }).catch(function () {
+      setLive(false, null);
+    });
+  }
+
+  var POLL_MS = 2000;
+
+  // Bootstrap retries until the base map loads, so a spectator who opens the
+  // page during a server blip recovers without a manual reload. The poll
+  // interval starts exactly once, on the first successful boot.
+  function boot() {
+    getJSON("./watch/world.json").then(function (world) {
+      paintMap(world);
+      poll();
+      setInterval(poll, POLL_MS);
+    }).catch(function () {
+      setLive(false, null);
+      setTimeout(boot, POLL_MS);
+    });
+  }
+  boot();
+})();
+</script>
+</body>
+</html>
+"""
+
+
+def _build_watch_html() -> str:
+    """Fill the texture hash formula into the page template.
+
+    The JS ``textured`` index is interpolated from
+    :data:`~understone.screen.texture._HASH_X` / ``_HASH_Y`` so the page's
+    formula is a derivation of the same two constants the Python renderer uses;
+    a retune of either moves both, and a guard test pins the agreement.
+    """
+    hash_expr = f"x * {texture._HASH_X} + y * {texture._HASH_Y}"
+    return _WATCH_HTML_TEMPLATE.replace("__HASH_EXPR__", hash_expr)
+
+
+WATCH_HTML = _build_watch_html()

examples/door-game/understone/world/__init__.py

@@ -0,0 +1,41 @@
+"""Content-pack loading — JSON on disk becomes a runtime ``World``."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+# The bundled starter pack ("The Vale of Understone"). Single source of truth
+# for where packaged content lives — the server's default world and the
+# scaffolder's template both resolve here.
+PACKAGED_WORLD_DIR = Path(__file__).resolve().parent / "data"
+
+# Zero-or-more bundled ALTERNATE worlds live one directory deeper, each in its
+# own ``<slug>/`` subdirectory carrying a ``world.json``. The Vale is special
+# (it is the default and lives at ``data/``); alternates are discovered here.
+PACKS_DIR = Path(__file__).resolve().parent / "packs"
+
+# The reserved slug of the default Vale — it is never a packs/ subdirectory but
+# is always listed first by the discovery helper below.
+VALE_SLUG = "vale"
+
+
+def bundled_world_dirs() -> list[tuple[str, Path]]:
+    """Return every bundled world as ``(slug, directory)``, the Vale first.
+
+    The default Vale (slug :data:`VALE_SLUG`, the ``data/`` directory) always
+    leads; the alternates follow in slug-alphabetical order. An alternate is
+    any immediate subdirectory of :data:`PACKS_DIR` that contains a
+    ``world.json`` — non-pack files (the README placeholder) and directories
+    without a world file are skipped, so the list is exactly the loadable
+    worlds. This is the single discovery path the ``worlds`` listing and any
+    future world resolver share.
+    """
+    found: list[tuple[str, Path]] = [(VALE_SLUG, PACKAGED_WORLD_DIR)]
+    if PACKS_DIR.is_dir():
+        alternates = [
+            (entry.name, entry)
+            for entry in PACKS_DIR.iterdir()
+            if entry.is_dir() and (entry / "world.json").is_file()
+        ]
+        found.extend(sorted(alternates, key=lambda pair: pair[0]))
+    return found

examples/door-game/understone/world/data/events.json

@@ -0,0 +1,102 @@
+{
+  "events": [
+    {
+      "kind": "fight",
+      "weight": 82,
+      "text": "Something snarls out of the brush."
+    },
+    {
+      "kind": "gold",
+      "weight": 8,
+      "text": "a rotted coin-purse half-buried in moss",
+      "min": 4,
+      "max": 12
+    },
+    {
+      "kind": "gold",
+      "weight": 7,
+      "text": "a few coins spilled from some luckless traveller",
+      "min": 2,
+      "max": 9
+    },
+    {
+      "kind": "gold",
+      "weight": 2,
+      "text": "a hoard-cache prised from beneath a toppled menhir",
+      "min": 40,
+      "max": 80
+    },
+    {
+      "kind": "heal",
+      "weight": 5,
+      "text": "a clearwater spring",
+      "min": 5,
+      "max": 12
+    },
+    {
+      "kind": "heal",
+      "weight": 5,
+      "text": "a quiet fae blessing",
+      "min": 4,
+      "max": 10
+    },
+    {
+      "kind": "heal",
+      "weight": 5,
+      "text": "a moss-bed where weary travellers mend",
+      "min": 6,
+      "max": 14
+    },
+    {
+      "kind": "trap",
+      "weight": 5,
+      "text": "a snare of old briars",
+      "min": 3,
+      "max": 9
+    },
+    {
+      "kind": "trap",
+      "weight": 5,
+      "text": "loose stones twist your ankle",
+      "min": 2,
+      "max": 8
+    },
+    {
+      "kind": "trap",
+      "weight": 5,
+      "text": "a hidden pit-deadfall, its cover long rotted through",
+      "min": 4,
+      "max": 11
+    },
+    {
+      "kind": "lore",
+      "weight": 3,
+      "text": "an old waystone, its rune worn to a coiled, scaled shape."
+    },
+    {
+      "kind": "lore",
+      "weight": 3,
+      "text": "the wind carries a low note from the east, like something vast turning in its sleep."
+    },
+    {
+      "kind": "lore",
+      "weight": 4,
+      "text": "a charcoal sketch nailed to a tree: a stair of stone descending into a great open mouth."
+    },
+    {
+      "kind": "lore",
+      "weight": 3,
+      "text": "a scorched ring in the grass where no plant grows, the soil still faintly warm."
+    },
+    {
+      "kind": "lore",
+      "weight": 3,
+      "text": "a ranger's cairn marking the dungeon road, three skulls set facing the deep as warning."
+    },
+    {
+      "kind": "lore",
+      "weight": 4,
+      "text": "fishermen swear the vale lake has no bottom, and that on still nights it breathes."
+    }
+  ]
+}

examples/door-game/understone/world/data/items.json

@@ -0,0 +1,85 @@
+[
+  {
+    "id": "rusty_dagger",
+    "name": "Rusty Dagger",
+    "slot": "weapon",
+    "atk": 2,
+    "price": 0
+  },
+  {
+    "id": "short_sword",
+    "name": "Short Sword",
+    "slot": "weapon",
+    "atk": 5,
+    "price": 40
+  },
+  {
+    "id": "iron_sword",
+    "name": "Iron Sword",
+    "slot": "weapon",
+    "atk": 7,
+    "price": 80
+  },
+  {
+    "id": "war_axe",
+    "name": "War Axe",
+    "slot": "weapon",
+    "atk": 9,
+    "price": 120
+  },
+  {
+    "id": "cloth_tunic",
+    "name": "Cloth Tunic",
+    "slot": "armor",
+    "def": 1,
+    "price": 0
+  },
+  {
+    "id": "padded_jerkin",
+    "name": "Padded Jerkin",
+    "slot": "armor",
+    "def": 2,
+    "price": 25
+  },
+  {
+    "id": "leather_armor",
+    "name": "Leather Armor",
+    "slot": "armor",
+    "def": 3,
+    "price": 50
+  },
+  {
+    "id": "chainmail",
+    "name": "Chainmail",
+    "slot": "armor",
+    "def": 6,
+    "price": 140
+  },
+  {
+    "id": "minor_potion",
+    "name": "Minor Potion",
+    "slot": "consumable",
+    "heal": 15,
+    "price": 12
+  },
+  {
+    "id": "greater_potion",
+    "name": "Greater Potion",
+    "slot": "consumable",
+    "heal": 40,
+    "price": 35
+  },
+  {
+    "id": "elixir_of_the_vale",
+    "name": "Elixir of the Vale",
+    "slot": "consumable",
+    "heal": 70,
+    "price": 60
+  },
+  {
+    "id": "iron_ore",
+    "name": "Iron Ore",
+    "slot": "material",
+    "price": 0
+  }
+]

examples/door-game/understone/world/data/locations.json

@@ -0,0 +1,53 @@
+{
+  "inn": {
+    "kind": "inn",
+    "name": "The Sleeping Drake",
+    "glyph": "⌂",
+    "color": "inn",
+    "actions": ["rest", "deposit", "withdraw", "gamble", "leave"],
+    "flavor": [
+      "Lamplight pools on worn oak tables.",
+      "The innkeeper nods toward the hearth.",
+      "A night's rest restores you fully.",
+      "An iron strongbox by the bar keeps coin safe from sleeping-robbers.",
+      "In the corner, a dice cup waits for a wager."
+    ]
+  },
+  "shop": {
+    "kind": "shop",
+    "name": "Gravel & Sons Outfitters",
+    "glyph": "$",
+    "color": "shop",
+    "actions": ["buy", "sell", "forge", "leave"],
+    "flavor": [
+      "Racks of steel and leather line the walls.",
+      "Buying a weapon or armour equips it at once.",
+      "Potions go into your satchel, to quaff when the need is dire.",
+      "The forge glows: bring coin to better your blade or your guard.",
+      "Old gear sells back for half its price."
+    ]
+  },
+  "healer": {
+    "kind": "healer",
+    "name": "The Quiet Shrine",
+    "glyph": "✚",
+    "color": "healer",
+    "actions": ["heal", "leave"],
+    "flavor": [
+      "Incense curls beneath a still blue flame.",
+      "The keeper mends wounds for coin, per point of vigour."
+    ]
+  },
+  "dungeon": {
+    "kind": "dungeon",
+    "name": "The Understone Deep",
+    "glyph": "∩",
+    "color": "dungeon",
+    "actions": ["descend", "challenge", "leave"],
+    "flavor": [
+      "A cold throat of stone descends into dark.",
+      "To descend is to face a troll, then something worse.",
+      "Deeper still, the old tales say, the Wyrm Below coils and waits."
+    ]
+  }
+}

examples/door-game/understone/world/data/monsters.json

@@ -0,0 +1,125 @@
+[
+  {
+    "tier": 1,
+    "name": "Field Rat",
+    "hp": 6,
+    "atk": 3,
+    "def": 0,
+    "xp": 8,
+    "gold": 3
+  },
+  {
+    "tier": 1,
+    "name": "Mud Hare",
+    "hp": 7,
+    "atk": 5,
+    "def": 0,
+    "xp": 9,
+    "gold": 2
+  },
+  {
+    "tier": 2,
+    "name": "Goblin",
+    "hp": 12,
+    "atk": 4,
+    "def": 1,
+    "xp": 18,
+    "gold": 7
+  },
+  {
+    "tier": 2,
+    "name": "Bandit Scout",
+    "hp": 14,
+    "atk": 5,
+    "def": 1,
+    "xp": 20,
+    "gold": 9
+  },
+  {
+    "tier": 2,
+    "name": "the Gilded Stag",
+    "hp": 16,
+    "atk": 6,
+    "def": 2,
+    "xp": 40,
+    "gold": 60,
+    "weight": 1,
+    "rare": true
+  },
+  {
+    "tier": 3,
+    "name": "Forest Wolf",
+    "hp": 20,
+    "atk": 7,
+    "def": 2,
+    "xp": 35,
+    "gold": 14
+  },
+  {
+    "tier": 3,
+    "name": "Bog Stalker",
+    "hp": 22,
+    "atk": 8,
+    "def": 2,
+    "xp": 38,
+    "gold": 16
+  },
+  {
+    "tier": 3,
+    "name": "the Hollow Knight",
+    "hp": 30,
+    "atk": 11,
+    "def": 4,
+    "xp": 80,
+    "gold": 110,
+    "weight": 1,
+    "rare": true
+  },
+  {
+    "tier": 4,
+    "name": "Cave Troll",
+    "hp": 38,
+    "atk": 11,
+    "def": 4,
+    "xp": 70,
+    "gold": 30
+  },
+  {
+    "tier": 4,
+    "name": "Barrow Wight",
+    "hp": 35,
+    "atk": 12,
+    "def": 4,
+    "xp": 65,
+    "gold": 28
+  },
+  {
+    "tier": 5,
+    "name": "Stone Wyrm",
+    "hp": 60,
+    "atk": 18,
+    "def": 6,
+    "xp": 140,
+    "gold": 60
+  },
+  {
+    "tier": 5,
+    "name": "Vale Reaver",
+    "hp": 55,
+    "atk": 17,
+    "def": 6,
+    "xp": 130,
+    "gold": 55
+  },
+  {
+    "tier": 6,
+    "name": "the Wyrm Below",
+    "hp": 120,
+    "atk": 24,
+    "def": 8,
+    "xp": 400,
+    "gold": 250,
+    "boss": true,
+    "id": "wyrm_below"
+  }
+]

examples/door-game/understone/world/data/terrain.json

@@ -0,0 +1,44 @@
+{
+  ".": {
+    "key": "grass",
+    "glyph": ".",
+    "walkable": true,
+    "encounter_rate": 0.1,
+    "color": "floor"
+  },
+  "T": {
+    "key": "tree",
+    "glyph": "♣",
+    "walkable": false,
+    "encounter_rate": 0.0,
+    "color": "tree"
+  },
+  "~": {
+    "key": "water",
+    "glyph": "≋",
+    "walkable": false,
+    "encounter_rate": 0.0,
+    "color": "water"
+  },
+  "=": {
+    "key": "road",
+    "glyph": "▒",
+    "walkable": true,
+    "encounter_rate": 0.02,
+    "color": "road"
+  },
+  "f": {
+    "key": "forest",
+    "glyph": "↑",
+    "walkable": true,
+    "encounter_rate": 0.25,
+    "color": "forest"
+  },
+  "#": {
+    "key": "wall",
+    "glyph": "█",
+    "walkable": false,
+    "encounter_rate": 0.0,
+    "color": "wall"
+  }
+}

examples/door-game/understone/world/data/world.json

@@ -0,0 +1,136 @@
+{
+  "name": "The Vale of Understone",
+  "width": 96,
+  "height": 48,
+  "spawn": [20, 24],
+  "legend": {
+    ".": "grass",
+    "T": "tree",
+    "~": "water",
+    "=": "road",
+    "f": "forest",
+    "#": "wall"
+  },
+  "terrain_rows": [
+    "TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT",
+    "TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT",
+    "TT..............................................f....f.ff.ffffffffffffffffffffffffffffffffffffTT",
+    "TT..............................................f..f...f.fffffffffffffffffffffffffffffffffffffTT",
+    "TT....~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ffffTT",
+    "TT....~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ffffTT",
+    "TT....~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ffffTT",
+    "TT....~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ffffTT",
+    "TT................................................f.ff.ff.fff.ffffffffffffffffffffffffffffffffTT",
+    "TT................................................f..ff.f.ffffffffffffffffffffffffffffffffffffTT",
+    "TT.....................................................ffffff.ffffffffffffffffffffffffffffffffTT",
+    "TT...................................................f.ff...ffffffff##f##fffffffffffffffffffffTT",
+    "TT.............................................f.f.f..f.ffffffffffff#=.f#fffffffffffffffffffffTT",
+    "TT....................................................f.f.ff.fffff====f##fffffffffffffffffffffTT",
+    "TT.................................................f.f...fff.fffff=fffffffffffffffffffffffffffTT",
+    "TT......................................................fff.ffffff=fffffffffffffffffffffffffffTT",
+    "TT................................................f...fffff.ffffff=fffffffffffffffffffffffffffTT",
+    "TT.........................................................ff.ffff=fffffffffffffffffffffffffffTT",
+    "TT...................................................f.f.ff.ffffff=fffffffffffffffffffffffffffTT",
+    "TT.....................................................ffff..fffff=fffffffffffffffffffffffffffTT",
+    "TT................................................f....f....ffffff=fffffffffffffffffffffffffffTT",
+    "TT................................................f..f.ffff..fffff=fffffffffffffffffffffffffffTT",
+    "TT.......................................................ff.f.ffff=fffffffffffffffffffffffffffTT",
+    "TT...............................................f.ff.f.....ffffff=fffffffffffffffffffffffffffTT",
+    "TT..................==.============================================fffffffffffffffffffffffffffTT",
+    "TT...............................................f..f....fff.fffffffffffffffffffffffffffffffffTT",
+    "TT...................................................ff.f.f.f.ffffffffffffffffffffffffffffffffTT",
+    "TT..................................................f...f.fff.ffffffffffffffffffffffffffffffffTT",
+    "TT...................................................f...ffff.ffffffffffffffffffffffffffffffffTT",
+    "TT..................................................ff.fff.ff.ffffffffffffffffffffffffffffffffTT",
+    "TT.................................................f......f.ffffffffffffffffffffffffffffffffffTT",
+    "TT....................................................ff..ff..ffffffffffffffffffffffffffffffffTT",
+    "TT....................................................ff..f..fffffffffffffffffffffffffffffffffTT",
+    "TT......................................................ffffffffffffffffffffffffffffffffffffffTT",
+    "TT....................................................f.fff...ffffffffffffffffffffffffffffffffTT",
+    "TT.................................................ff....fffffffffffffffffffffffffffffffffffffTT",
+    "TT...............................................f........ffffffffffffffffffffffffffffffffffffTT",
+    "TT..................................................f.ff.....fffffffffffffffffffffffffffffffffTT",
+    "TT...............................................f.f...ff.f..fffffffffffffffffffffffffffffffffTT",
+    "TT.....................................................ff..f.fffffffffffffffffffffffffffffffffTT",
+    "TT...................................................ff...ffffffffffffffffffffffffffffffffffffTT",
+    "TT................................................f....f.ffff.ffffffffffffffffffffffffffffffffTT",
+    "TT..................................................f...ff.fffffffffffffffffffffffffffffffffffTT",
+    "TT....................................................f.ff.f..ffffffffffffffffffffffffffffffffTT",
+    "TT.............................................ff......fffffffffffffffffffffffffffffffffffffffTT",
+    "TT................................................f.f...f....fffffffffffffffffffffffffffffffffTT",
+    "TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT",
+    "TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT"
+  ],
+  "locations": [
+    {
+      "key": "inn",
+      "x": 18,
+      "y": 24
+    },
+    {
+      "key": "shop",
+      "x": 22,
+      "y": 24
+    },
+    {
+      "key": "healer",
+      "x": 20,
+      "y": 22
+    },
+    {
+      "key": "dungeon",
+      "x": 70,
+      "y": 12
+    }
+  ],
+  "zones": [
+    {
+      "key": "forest_near",
+      "rect": [30, 18, 60, 36],
+      "tier_lo": 1,
+      "tier_hi": 2
+    },
+    {
+      "key": "dungeon_deep",
+      "rect": [66, 8, 80, 20],
+      "tier_lo": 3,
+      "tier_hi": 5
+    }
+  ],
+  "settings": {
+    "daily_turns": 10,
+    "rest_cost": 15,
+    "heal_cost_per_hp": 1,
+    "starting_gold": 37,
+    "starting_weapon": "rusty_dagger",
+    "starting_armor": "cloth_tunic",
+    "start_hp": 20,
+    "start_atk": 3,
+    "start_def": 0,
+    "xp_base": 100,
+    "growth": {
+      "max_hp": 6,
+      "atk": 2,
+      "def": 1
+    },
+    "bestow_daily_budget": 25,
+    "dungeon_tiers": [3, 4, 5],
+    "boss_monster": "wyrm_below",
+    "wyrm_min_level": 6,
+    "ambush_min_level": 3,
+    "ambush_level_band": 2,
+    "ambush_gold_pct": 25,
+    "post_daily_cap": 5,
+    "gamble_max_bet": 50,
+    "gamble_daily_cap": 5,
+    "satchel_max": 3,
+    "forge_base_cost": 60,
+    "forge_max_plus": 3,
+    "rare_drop_item": "greater_potion",
+    "forge_ore_item": "iron_ore",
+    "forge_ore_per_plus": 1,
+    "ore_dungeon_drop": 2,
+    "ore_forest_chance": 0.2,
+    "watch_theme": "phosphor"
+  }
+}