## What & why
**FN-8141 laundered a failed task into `done` with zero net changes and
no sign-off.** After the executor's
`bulk-step-completion-without-review` refusal fired (steps had no
APPROVE verdicts), the agent used the sanctioned skip affordance
(`fn_task_update status="skipped"`) on the remaining unreviewed steps.
Because every completion check counts `skipped` as complete, the task
then satisfied the exact condition the refusal was protecting, and
downstream **automatic** promotion (implicit `fn_task_done`,
self-healing `recoverStrandedCompletedTodoTasks`) moved it to in-review
— where the AI merger found an empty diff and finalized it as a no-op
`done`.
This PR restores the invariant: **steps skipped while a
bulk-step-completion refusal marker is active on the task are "tainted"
and cannot carry the task to review through any automatic path.** The
taint clears on an honest exit — an accepted `fn_task_done` (explicit or
non-tainted implicit) or an operator manual retry — so the legitimate
`PREMISE STALE` skip-then-done flow is unaffected.
## Design
- **Persisted marker**: new nullable `Task.bulkCompletionRefusalAt` (ISO
timestamp), stamped when the `bulk-step-completion-without-review`
refusal fires (explicit `fn_task_done` handler + implicit
`handleImplicitTaskDoneRefusal`). Survives requeue so a refusal on
attempt N taints attempt N+1's promotion. Full store plumbing (types,
descriptors, serialization, SQLite/PG schema + health self-heal).
- **Pure evaluator** `evaluateSkipBypassTaint(task)` in `@fusion/core`
(next to `evaluateNoCommitsNoOpFinalize`): `blocked` iff the marker is
set AND ≥1 step is `skipped`. Single rule every AUTO-promotion check
calls.
- **Clearing**: accepted explicit `fn_task_done`, accepted
implicit/retry completion (the success-reset `updateTask`s), and
`buildManualRetryResetPatch` (operator retry). A fresh lifecycle that
genuinely re-does the work leaves zero skipped steps, so it is never
blocked even if a marker lingers.
## Surface enumeration (every consumer of "all steps done/skipped" that
gates AUTO-promotion)
- **executor.ts**: `getCompletedTaskFinalizationDecision` (gated on the
`isTaskWorkComplete` branch only, never on an accepted `taskDone`);
`recoverCompletedTask` (shared chokepoint for unpause resume,
completed-task watchdog, orphan resume);
`evaluateImplicitCompletionRefusal` (both implicit-completion loops);
`isTaskAlreadyCompleteForNonContinuableSession`; graph merge-boundary
`getWorkflowMergeImplementationProofFailure`.
- **self-healing.ts**: `recoverCompletedTasks` (stuck in-progress) and
`recoverStrandedCompletedTodoTasks` (the exact FN-8141 promoter).
- **Verified-safe, left as-is**: per-step graph node projections
(executor ~6274/6298) and progress-render checks — they don't gate
whole-task auto-promotion.
## Test evidence
Scoped runs (all green):
```
CORE: pnpm --filter @fusion/core exec vitest run \
src/__tests__/skip-bypass-taint-guard.test.ts \
src/__tests__/skip-bypass-taint-persistence.test.ts \
src/__tests__/manual-retry-reset.test.ts
→ 17 passed
ENGINE: pnpm --filter @fusion/engine exec vitest run \
src/__tests__/executor-skip-bypass-taint.test.ts \
src/__tests__/self-healing.test.ts
→ 401 passed
```
Coverage: pure-evaluator (skip-before-refusal counts, skip-after-refusal
doesn't, taint-clearing, empty-marker/empty-steps edges); store
round-trip of the marker (set→read→clear); executor white-box (implicit
completion refused when tainted, allowed when clean or fully re-done,
graph merge-boundary reports missing proof, and the **explicit
`fn_task_done` PREMISE-STALE honest exit stays accepted**); self-healing
(FN-8141 sequence does not promote from either recovery path; a clean
legitimately-skipped task still promotes); manual-retry clears the
marker.
## Note on `pnpm verify:fast`
`verify:fast` currently fails at the workspace-artifact bootstrap on
**pre-existing** pi-SDK type errors in
`packages/engine/src/{auth-storage,pi,provider-registration}.ts` — the
FN-8145 upstream migration breakage (pi 0.80.x removed
`AuthStorage`/`ModelRegistry.create`). **None of those files are in this
diff.** `@fusion/core` builds clean (`packages/core build: Done`), and
`@fusion/engine` `tsc` reports **no errors in the files this PR
touches** (`executor.ts`, `self-healing.ts`); the only engine build
errors are the FN-8145 files. This base failure is the same condition
FN-8141 describes and is out of scope for this task.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Opus <noreply@anthropic.com>
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