name: concurrency-core description: "Concurrency design patterns & safety workflow. Use when you introduce or modify concurrency (threads/async/callbacks/queues/locks), parallelize for performance, or need a clear shutdown/cancellation strategy." metadata: short-description: Concurrency design patterns and planning

Purpose

Produce a Concurrency Plan with pattern-based choices so concurrent behavior is deliberate, safe, and testable.

When to use

Use this skill when you:

•add or change threads, async/await, callbacks, queues, locks, or executors
•parallelize work for performance or responsiveness
•introduce background workers, timers, or concurrent IO

How to use

•Open references/concurrency-core.md.
•Write a Concurrency Plan (use the template).
•Select an appropriate pattern (or justify why none fits).
•Identify shared mutable state and choose a containment strategy.
•Define cancellation/shutdown and error propagation.
•Define observability hooks for diagnosing concurrent behavior.
•Define verification strategy; invoke $thread-safety-tooling if multi-threading exists.

Output expectation

•Output the full Concurrency Plan sections.
•Add a short Risks & mitigations summary.