feat(task): task-local runtime thinking effort state with per-request override (DTE series 2/5) - #1523

≤400-line redo of #1338 — DTE series 2/5, unit 3/5

Task-local runtime thinking-effort state on Task: the in-memory override
channel, its per-request delivery at all four createMessage sites, and the
profile-switch re-capture in updateApiConfiguration. Transient state only — nothing is persisted; persistence is the next unit (U4).

Stack

• PR base: upstream main @ 0dbd5846f (cross-fork PR — head easonLiangWorldedtech:feat/dte-v2-3-task-runtime-effort; stack branches live in the fork — no push access to create them here)
• Stack base: feat/dte-v2-2-per-request-effort @ 069c34b9a (U2, upstream PR feat(api): per-request thinking effort override and adaptive effort envelope (DTE series 2/5) #1522, new tip — carries U1's post-main-sync head e89cceddd and the advanced upstream main tip 0dbd5846f merged in)
• Stack sync: first sync f97f8d999 merged U2's tip 18f488fa5 (U1 final CR fixes 53f22dc in); second sync c5b48aa7e merged U2's new tip efbd336e5 (U1's final head 39762bf81 — the last feat(settings): dynamic thinking effort experimental toggle (DTE-1) #1521 CR fix — in); third (main) sync e8c66cfad (this head) merges U2's post-main-sync tip 069c34b9a (upstream main advanced 0d937c050 → 0dbd5846f: v3.82.0 release prep Release v3.82.0 #1533, GPT-6 Astra [Feat] Add verified GPT-6 Astra support across providers #1506, DeepSeek V4 Flash Vision [Feat] Add DeepSeek V4 Flash Vision Exp support #1488, the throwIfAborted helper + completePrompt options regression tests feat(api): add throwIfAborted helper and completePrompt options regression tests #1288, and the async Task.dispose() test-teardown fix [Fix] Unit tests report teardown errors after Task cleanup #1527). One conflict in src/core/task/Task.ts resolved: main's async dispose(): Promise<void> restructure (memoized disposalPromise + disposeOnce()) kept, with U3's 4-line DTE JSDoc above the new dispose(); the test's afterEach now awaits task.dispose() per the repo idiom. Standalone budget 398 at this head (amended to 403 by the CR re-review fix in commit 1edd728c4, then to 418 by the follow-up CR fix in commit 1087fcbd4, see below)
• Content source: feat/dte-trial-all union 27a2e97df (tag dte-legacy/union), U3 slice
• Related: DTE-v2 final ship plan - 39-unit 400-line redo of the DTE series (supersedes #28) easonLiangWorldedtech/Zoo-Code#35 (DTE-v2 tracking ledger)

GitHub's displayed diff vs main is cumulative over the unmerged lower units
(U1 #1521, U2 #1522); the standalone range below is the review target — the displayed number shrinks as they merge. Merge this PR only after its stack
base PR has merged.

Budget (plan §2: a+d ≤400 soft target; ≤1000 hard)

2 files changed, 417 insertions(+), 1 deletion(-) = 418 — soft target 400 exceeded by 18, CR-driven (see the amendments below); hard cap 1000 ✓

Budget deviation note (plan §2.6). The plan estimated U3 at ~355
(Task +132/− + tests ~20); those numbers were stale. Measured against the
union, the U3 slice is Task +105/− + a 311-line test file = 417 > 400. Per
§2.6 (no budget bypass), the dispose boundary group is split into U4:
the task-end override reset (6 Task lines + 3 DTE JSDoc lines) and its
12-line describe("dispose") test block. This matches the plan's own U4 scope
line ("persistence + boundary cases"). U3 keeps the generic 4-line dispose()
JSDoc; U4 expands it with the DTE sentence alongside the reset code.

CR re-review amendment (2026-09-05, review 5120440807). The main-sync
head re-review requested the task-end override reset to live in
disposeOnce() of this unit (so a retained disposed task never serves a stale
override, and the dispose() JSDoc's "resets transient task-local state"
claim is accurate), plus the test afterEach teardown to call
await task.dispose() unconditionally (the !task.abort guard had skipped
disposal of aborted tasks). Both land here in commit 1edd728c4 (+5/−1 ⇒
standalone 398 → 403 — a 3-line overshoot of the soft target, within the 1000
hard cap). Under the split above, U4 loses the reset code it had carried; its
12-line dispose-boundary test block stays with U4 (it now exercises this
unit's reset on the stacked tree).

CR follow-up fix (2026-09-06, review thread comment 3942121231). The
re-review of head 1edd728c4 found that the unconditional field clears in
disposeOnce() left the override behind in apiConfiguration.reasoningEffort
and the built api handler — both are populated by
setRuntimeThinkingEffort, so a retained disposed task could still expose the
override through those copies. Commit 1087fcbd4 replaces the three
assignments with the standard clearing call this.setRuntimeThinkingEffort(undefined) —
which restores apiConfiguration/api from preOverrideReasoningEffort
(read before it is cleared) and then clears the runtime fields — and adds a
14-line describe("dispose") killing-test block asserting the clear and the
restore (Task.ts net +1; standalone 403 → 418 a+d — CR-driven, ≤1000 hard cap).

Provenance / fidelity

• Task.ts: 3-way git merge-file — base 39bdfb188 (= 6ea45b36a^),
  ours = U2 head, theirs = 90b47b053 (the last U3 commit, before the U4
  persistence work). Zero conflicts. A whole-file extract was impossible:
  the union's Task.ts carries U14-orchestrator and U4/U5 content
  (215+/241− vs U1 head), and per-commit git apply --3way of the U3 patches
  fails on upstream base drift.
• Test file: byte-exact 90b47b053 version (311 lines) minus the dispose
  describe (12 lines + separator), plus the 3 mutation-killing assertion
  lines below = 301 lines; the header comment is trimmed to the U3 scope
  ("the task-end reset in dispose()" clause moves with U4).
• U4 content excluded: taskMetadata.ts / history.ts persistence changes,
  the describe("history persistence round-trip") and
  describe("abortTask final save") blocks, and the HistoryItem import
  (unused in the U3 slice).
• src/eslint-suppressions.json: untouched. The union's +21 suppression-count
  deltas vs the stack base are all in files owned by other units
  (gemini-format.spec.ts 5→6, ask-queued-message-drain.spec.ts 18→32,
  newTaskTool.spec.ts 26→31, new extension.ts 1) — none U3-owned.

Out of scope (next units)

• U4 (DTE-2c): persist task thinking effort to history items,
  taskMetadata merge propagation, and the task-end override reset split out
  above (dispose boundary + its test).
• U5 (DTE-2d): the Anthropic output_config.effort adaptive envelope.

Mutation-diff fix (killing assertions, plan L42 — same PR)

The first CI mutation-diff run (head d0b1a3dcd) reported 2 Survived
ConditionalExpression mutants — both on the two ternaries this unit
introduces:

The complementary variants (L1683-true, L1721-false) were already killed by
the existing toBe("test-source") and toEqual({ reasoningEffort: "high" })
assertions.

Local dev-stage gate (skill §5.1) on the latest CR-fix head 1087fcbd4:
node scripts/stryker-diff.mjs ci --base 069c34b9a --head 1087fcbd4 — extension 36 changed lines, 26 valid mutants, 26 Killed, 0 Survived / 0 NoCoverage, exit 0 (previous CR-fix head 1edd728c4: 38 lines, 25/25 Killed).

Verification (local, head 1087fcbd4)

• pnpm --dir src exec eslint --prune-suppressions --max-warnings=0 core/task/Task.ts core/task/__tests__/Task.runtime-thinking-effort.test.ts — exit 0 (re-run on 1087fcbd4; no suppression-count change)
• pnpm check-types — 11/11 projects
• pnpm --dir src exec vitest run core/task/__tests__/Task.runtime-thinking-effort.test.ts — 9/9 (re-run on 1087fcbd4, 4.16 s; includes the new dispose killing test)
• git diff --shortstat 069c34b9a HEAD — 417+/1− = 418 (CR fixes +19/−4 vs 1edd728c4; soft overshoot documented above, ≤1000 hard)
• mutation-diff gate (dev stage, skill §5.1) on 1087fcbd4 — exit 0, 26/26 Killed (see fix above)