concurrency-core

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","requires":["references/concurrency-core.md"]}

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

0. Open references/concurrency-core.md.
1. Write a Concurrency Plan (use the template).
2. Select an appropriate pattern (or justify why none fits).
3. Identify shared mutable state and choose a containment strategy.
4. Define cancellation/shutdown and error propagation.
5. Define observability hooks for diagnosing concurrent behavior.
6. 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.