Some serving setups emit model reasoning inline with no think tags and no
reasoning_content at all — nothing any parser can segregate (measured live
on the dev vLLM: 20/20 sampled completions, streamed and not, proxied and
direct). The drain seam correctly passes unmarked prose through, so it
became the artifact on every bounded-artifact lane: workstream titles
("Thinking Process:"), compaction summaries that were ~90% chain-of-
thought, and the web-fetch tool results #940 reports — which then ride
every following turn as context.
Three coordinated changes:
* Utility lanes ask for no reasoning. _utility_completion (title,
compaction, web-fetch extraction) pins the alias's declared thinking
toggle off and withholds every reasoning-effort channel — the relayed
session knob, the lane rung, the definition default, and the graded
template key — via lane_without_thinking / lane_thinking_suppressed,
the same suppression omni transcription already used (now shared as
thinking_off_template_kwargs). Measured end-to-end: the extraction
that returned 3.7k chars of reasoning returns a 258-char answer.
* server_parses_reasoning capability. A backend that segregates
reasoning into its own channel declares it, and the inline tag scan
turns off on every lane: the drain seam, the interactive splitter
(which now reads the ACTIVE stream's capabilities via the creation-
time handoff register, never the primary alias's), and the title
lane's cosmetic peel — so prose that merely quotes a tag can no
longer be misrouted, and the utility suppression stands down where
reasoning costs the artifact nothing. The built-in commercial
capability tables declare it wholesale (known models and table-miss
defaults); local compat lanes keep the passthrough default the scan
exists for. Bool-typed capability overrides coerce string spellings
instead of truthiness-flipping on hand-edited JSON.
* Title selection follows the prompt's contract, not line position:
the last line within the word cap that ends in a word character —
rejecting explanation sentences, sign-offs, parentheticals, and
reasoning headings in any script (terminal punctuation carries
unspaced scripts where whitespace word counts are meaningless) —
else the last non-empty line. 20/20 captured live responses title
correctly (9/20 before, unchanged since well before the seam
unification: the old and new pipelines scored identically on every
sample, so the regression source was the backend's output shape,
not #965).
Also folded in from the review round: a think tag split across a
reasoning-delta boundary reassembles in the drain (partial-tag tail
carry; tool boundaries still flush), Turn.text joins text blocks with a
newline so multi-block answers stop fusing words in notification bodies
and every flattened read, the notify hook reads final_assistant_text
directly instead of through a one-line shim, web-fetch extraction uses
the shared _non_blank_or fallback, and the judge/output-guard suites use
real ModelCapabilities instead of truthy mock attributes.
Closes#940.
Passthrough servers (parserless vLLM/llama.cpp, LM Studio, bare
gateways) emit reasoning as literal <think>/<reasoning> blocks inside
content, and only three of nine drained lanes stripped them: web_fetch
tool results persisted raw think blocks into every following turn
(#940), judge verdicts parsed through tag noise, and a draft verdict
inside a think block could shadow the real one at the output guard.
One rule at the seam now. drain_stream accumulates content in RUNS
bounded by interleaving signals (provider-parsed reasoning deltas,
tool-call deltas) with the interactive consumer's within-chunk ordering
— reasoning, then content, then the tool-call close — and splits each
run through split_inline_reasoning, the one-shot form of the
interactive lane's ThinkTagSplitter: a pure raw split, exactly
equivalent to the streaming form on every catalog case. One trim policy
exists and the drain owns it: blank edge lines are trimmed once over
the joined runs when a tag was consumed, so tag residue dies at the
edges while genuine inter-run paragraph separators survive. Extracted
text is appended to result.reasoning after any server-parsed reasoning
with a blank-line boundary and rides the native lane as the
reasoning_text synth block. Orphan CLOSE tags deliberately pass through
byte-identical: a close whose open never arrived is indistinguishable
from prose QUOTING the tag, and drained lanes routinely quote
third-party text — reclassifying would let a malicious page containing
the literal tag destroy the extraction that cites it. The title lane
keeps a local rfind peel as display-string formatting. The citations
footer folds only onto non-blank content — sourcing for an answer that
does not exist is dropped rather than handed to emptiness checks as a
footer-only "answer".
Every private strip is deleted: the title lane's strip, the summarizer
strip, _strip_reasoning itself, and the optimizer's five regexes
(_strip_markdown_fence is now the one fence rule, applied to normalized
model output only, never to or-fallback values). Think-only and
whitespace-only responses drain to blank content, and every lane's
no-answer fallback gates on blankness: web_fetch returns an honest
extraction-error card, the intent judge takes the empty-retry ladder,
the task-agent synthesis reports "(no output)", and the optimizer keeps
the current observer system and prompt verbatim on no-answer passes.
Final-say reads (optimizer analyst, eval final_content, the notify
hook) use trajectory.final_assistant_text — the last assistant turn
only, never an earlier narration presented as the conclusion — while
last_assistant_text is the salvage walk (task_agent partial-work
recovery), skipping tool-call-only, all-reasoning, and whitespace-only
turns. Perception memoizes every completed description immediately,
including an empty one — one perceive per key, ever — under a
commit-lock guard so an empty result never overwrites a concurrently
memoized real description; an all-reasoning perception model pins the
placeholder until restart, and the remediation is server-side (a
reasoning parser or the template thinking toggle on the perception
alias). A true double-reasoning shape (inline-extracted text alongside
a native reasoning block) logs chars-only at the drain, where it is
distinguishable from the routine reasoning_delta mirror.
The dialect's semantics are pinned as one table
(tests/_reasoning_dialect.py) driven through shared fixtures
(think_tag_stream, seam_provider): one-shot conformance, the exact
one-shot/streaming equivalence property, the drain seam rules including
quoted-tag safety, run-boundary and separator-preservation pins,
per-lane pins for all nine lanes, and the empty-content assistant wire
shape.
Closes#965. Closes#940.
ChatSession.messages flips from list[dict] to list[Turn] — the in-memory
canonical trajectory. Reads migrate to typed fields (turn.role, turn.text,
turn.tool_calls); appends and assignments go through turn_from_dict /
turns_from_dicts; the fork bulk-save and retry's multipart check read via
turn_to_dict. _full_messages lowers Turns→dicts at the wire boundary — the
fold/repair and provider translators still consume dicts until the next slice.
The token-accounting helpers accept a dict or a Turn.
Non-session consumers migrate too: coordinator_idle_observer and eval to typed
fields (mypy-enumerated), and server's last-assistant extractor via turn_to_dict
(an Any-typed call site mypy could not flag). An all-text multipart content
list (the unreadable-attachment placeholder path) now round-trips faithfully
through the adapter (single text block → str, multiple → list).
Tests that inspected session.messages as dicts read it through the
dicts_from_turns / turn_to_dict bridge; those that built it pass dicts through
turns_from_dicts / turn_from_dict. Byte-identical wire harness; full non-live
suite green (7130).
GenerationCancelled extends BaseException, not Exception, so it bypassed
the except handler in _run_initial. The finally block ran but
_extract_last_assistant_content returned "" (response never appended to
messages), and _fire_notify_targets bailed on the empty content guard.
Fixes:
- Catch BaseException (not just Exception) in _run_initial so
GenerationCancelled is handled and the UI state is cleaned up
- Remove the empty-content suppression in _fire_notify_targets —
scheduled tasks should always deliver, even with a fallback message
when no output was captured
Patrick Buckley