# Swift Concurrency Pro

Reviews Swift code for concurrency correctness, modern API usage, and common...

- Repository: https://github.com/jacklandrin/OnlySwitch (6026 stars)
- Category: Mobile
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add jacklandrin/OnlySwitch --skill swift-concurrency-pro -g -a claude-code -y`
Codex: `npx skills add jacklandrin/OnlySwitch --skill swift-concurrency-pro -g -a codex -y`
Cursor: `npx skills add jacklandrin/OnlySwitch --skill swift-concurrency-pro -g -a cursor -y`
Gemini CLI: `npx skills add jacklandrin/OnlySwitch --skill swift-concurrency-pro -g -a gemini-cli -y`

## Description

Reviews Swift code for concurrency correctness, modern API usage, and common async/await pitfalls. Use when reading, writing, or reviewing Swift concurrency code.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

Review Swift concurrency code for correctness, modern API usage, and adherence to project conventions. Report only genuine problems - do not nitpick or invent issues.

Review process:

1. Scan for known-dangerous patterns using `references/hotspots.md` to prioritize what to inspect.
1. Check for recent Swift 6.2 concurrency behavior using `references/new-features.md`.
1. Validate actor usage for reentrancy and isolation correctness using `references/actors.md`.
1. Ensure structured concurrency is preferred over unstructured where appropriate using `references/structured.md`.
1. Check unstructured task usage for correctness using `references/unstructured.md`.
1. Verify cancellation is handled correctly using `references/cancellation.md`.
1. Validate async stream and continuation usage using `references/async-streams.md`.
1. Check bridging code between sync and async worlds using `references/bridging.md`.
1. Review any legacy concurrency migrations using `references/interop.md`.
1. Cross-check against common failure modes using `references/bug-patterns.md`.
1. If the project has strict-concurrency errors, map diagnostics to fixes using `references/diagnostics.md`.
1. If reviewing tests, check async test patterns using `references/testing.md`.

If doing a partial review, load only the relevant reference files.


## Core Instructions

The rest: https://github.com/jacklandrin/OnlySwitch/blob/HEAD/doc/skills/swift-concurrency-pro/SKILL.md