state-mutation-locking

name	state-mutation-locking
description	Durable state mutation and locking workflow.
origin	pi-crew
triggers	["modify manifest","update tasks","stale reconciliation","cancel run","respond to task"]

state-mutation-locking

Use this skill before modifying pi-crew run state.

Source patterns distilled

• src/state/locks.ts — run-level sync/async locks
• src/state/state-store.ts — manifest/tasks persistence
• src/state/contracts.ts — allowed status transitions
• src/state/mailbox.ts, src/state/task-claims.ts, src/state/atomic-write.ts
• src/runtime/crash-recovery.ts, src/runtime/stale-reconciler.ts, src/runtime/team-runner.ts

Rules

• Mutations to a run's manifest.json, tasks.json, mailbox delivery state, claims, or recovery status must be protected by a run lock when concurrent actions are possible.
• Re-read manifest/tasks inside the lock before making a decision; pre-lock reads are only for locating the run.
• Persist with atomic write helpers (atomicWriteJson, async variants, or state-store helpers). Do not partially write JSON files.
• Respect status contracts. Do not transition terminal tasks/runs unless the action explicitly supports force semantics.
• Separate analysis from persistence: pure reconcilers should return intended repaired state; locked callers should persist it.
• In retry/resume paths, reload fresh task status immediately before execution and skip if the task is no longer retryable/runnable.
• Include event-log entries for externally visible state changes.

Enforcement — State Mutation Locking Gate

Before mutating run state, verify:

• Run lock acquired before mutation (concurrent actions possible)
• Manifest/tasks re-read inside the lock before decision
• Atomic write helpers used (atomicWriteJson or state-store helpers)
• Status contracts respected (no terminal transitions without force semantics)
• Event-log entries emitted for externally visible state changes
• Retry paths reload fresh task status before execution

If ANY answer is NO → Stop. Verify locking and atomicity before mutating.

Anti-patterns

• Reading state, waiting/doing async work, then writing the old copy.
• Updating tasks.json from a reconciler or watcher without a lock.
• Cancelling/responding to runs owned by another session.
• Using fs.writeFileSync for JSON state outside atomic helpers.

Verification

cd pi-crew
npx tsc --noEmit
node --experimental-strip-types --test test/unit/cancel-ownership.test.ts test/unit/respond-tool.test.ts test/unit/stale-reconciler.test.ts test/unit/api-claim.test.ts
npm test