`analysis-agent`/`task-agent`/`review-agent`: primary-Skill-selected for races, locks, optimistic conflicts, or worker overlap; never task owner; skip without concurrency impact.
Installs into .claude/skills of the current project.
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---
name: concurrency-control
description: "`analysis-agent`/`task-agent`/`review-agent`: primary-Skill-selected for races, locks, optimistic conflicts, or worker overlap; never task owner; skip without concurrency impact."
---
# concurrency-control
## Registry Trigger
**Use when**
- control concurrent writes races locks leases optimistic conflicts and queues
**Do not use when**
- no task-local concurrency control decision is required
## Skill Role
Preserve named invariants under overlapping writes, retries, leases, redelivery, and stale ownership.
## High-Value Rules
- Select the narrowest current-store control that preserves the named invariant under reachable overlap.
- Define conflict outcomes, retry and idempotence, lock or lease lifecycle, order, and fencing for affected actors.
- Prove allowed and forbidden concurrent outcomes.
## Anti-Patterns
- Local success substituted for evidence of the concurrency control contract.
## Stop Conditions
Escalate when money, inventory, permissions, quotas, or cross-service reservations can violate an invariant, a distributed lease lacks fencing, or recovery is unproven.
## Output Contract
- concurrency plan with critical sections locks conflicts and tests, evidence, and proof limits
## Targeted References
| Path | Type | Load when | Do not load when | Required by | Required output |
|---|---|---|---|---|---|
| [benchmarks and patterns](references/benchmarks-and-patterns.md) | benchmark-pattern | Lost updates, stale ownership, deadlocks, or contention need mechanism selection | No overlapping actor can mutate the affected invariant | analysis-agent, task-agent, review-agent | option-comparison, selected-approach |
| [checklist](references/checklist.md) | decision-checklist | Concurrency spans retries, cancellation or timeout, lease ownership or another time-derived ownership claim, lock order, version reuse or ABA, duplicate effects, or scheduling fairness | The resource has one serialized owner | analysis-agent, task-agent, review-agent | checklist-result, residual-risk |
| [evidence patterns](references/evidence-patterns.md) | evidence-pattern | Safety claims require synchronized overlap or contention artifacts | No interleaving or ownership claim awaits proof | analysis-agent, task-agent, review-agent | evidence-record, proof-limit, residual-risk |
