`man` and `math` duplicated capabilities already reachable through
`bash`; `plan_agent` is better expressed as a `task_agent` running a
planning skill, and carried a large amount of special-case machinery
(plan-review gate, refinement loop, per-kind model routing). Removing
all three shrinks the tool surface and cuts per-call token cost.
Also removed, as dead-once-the-tools-are-gone:
- the `math` sandbox executor (`turnstone.core.sandbox`) and its
`[sandbox]` extra; the eval analyst now runs bash-only
- the read-only `AGENT_TOOLS` sub-agent tool set and the `agent`
tool-metadata key (`task_agent`/`TASK_AGENT_TOOLS` retained)
- the plan-review protocol end to end: the `on_plan_review` UI hook,
`resolve_plan`, `POST /v1/api/plan` + `POST /v1/api/route/plan`,
the `plan_review`/`plan_resolved` SSE events, and their Python SDK /
TypeScript SDK / OpenAPI / frontend / Discord+Slack bindings
- the `model.plan_alias` / `model.plan_effort` settings and the
registry `plan_model` / `plan_effort` routing fields
TOOLS 31->28, TASK_AGENT_TOOLS 13->11; COORDINATOR_TOOLS unchanged.
BREAKING CHANGE: removes the `man`, `math`, `plan_agent` tools, the
plan-review SSE/HTTP/SDK surface, and the plan_* model-routing settings
from the experimental 1.6 line.
Replace linear optimization chain with UCB1 evolution tree. Each
iteration selects the most promising node to extend, preventing
irrecoverable collapse from bad edits. Also adds improvement-based
delta feedback to the optimizer and optional holdout set separation.
Inspired by "Learning to Self-Evolve" (arXiv:2603.18620).
Patrick Buckley