Swift Concurrency Agent Skill

A Swift concurrency skill: safe work with actors and tasks, data race triage and Swift 6 migration

  • 1,715 ★ on the repository
  • Last commit
  • MIT
Skill

Minimal access

Why this level

  • The skill consists of instructions and references; the agent changes code under the user's control
All reasons and checks

avdlee/swift-concurrency-agent-skill

Install

Manual install

npx skills@latest add https://github.com/avdlee/swift-concurrency-agent-skill --skill swift-concurrency

The recommended way via the skills manager.

Access and checks

How we review

Minimal accessThe tool runs nothing and makes no network calls.

  • The skill consists of instructions and references; the agent changes code under the user's control

This is third-party code. Review the repository files before installing.

What it does

The skill gives a coding agent expert Swift concurrency rules in the open Agent Skills format. It walks the agent through a short algorithm: first determine the language mode, strict concurrency level and isolation boundaries from the project settings, then propose the smallest safe change. The material is split into references on actors, tasks, Sendable, async sequences, memory management, testing, Core Data and migration. The skill helps triage isolation errors and data races, rewrite code to async and await, and enable strict checks incrementally. It sets explicit guardrails: do not apply MainActor as a blanket fix and do not refactor extra during migration.

Who it is for. For Swift developers moving to strict concurrency and Swift 6 or debugging data races.

Good fit when

  • The compiler complains about actor isolation or Sendable
  • You need to move a project to strict concurrency or Swift 6
  • You need to rewrite closure-based code to async and await without races

Not a fit when

  • The task is unrelated to Swift and its concurrency
  • You need a tool that changes code itself rather than references and rules for the agent

Example request

Use the swift-concurrency skill and triage the actor isolation error in this file, propose the smallest safe fix

Limitations

The skill provides rules and references; the agent changes code under your control. Some links point to the author's paid course and are only for deeper study, while the skill itself is MIT licensed. For isolation boundaries and project settings the skill asks for confirmation rather than guessing.

How to disable. Remove the skill with the manager you installed it with, for example npx skills@latest, or delete the skills/swift-concurrency folder from the skills directory. If installed as a plugin, remove it via /plugin.

FAQ

Which agents does the skill work with?

Any that support the open Agent Skills format. The repository has manifests for Claude Code, Cursor, Codex and pi, and it installs via skills.sh, Gemini CLI or manually.

Is the skill paid?

No, the skill itself is MIT licensed. Only the author's course is paid; its links are given for deeper study.

Discussion

No questions or reviews yet.

Skills

A set of 16 engineering skills for agents: Apple platform work, macOS packaging, React performance, code review and refactoring

SkillExtended access4KRepository stars

A skill that speeds up Xcode builds: benchmarks clean and incremental builds, finds bottlenecks and tunes project settings

SkillExtended access1.3KRepository stars

A library of 30-plus instruction skills for coding agents: planning, building, testing, hallucination guards and shipping

SkillMinimal access217Repository stars
Official

Skills from the Dart team: tests and mocks, analysis and dart fix, CLI apps, FFI, documentation and package conflict fixes for an AI agent

SkillMinimal access552Repository stars
Editors’ pick

A skill set from the Kotlin team for agents: Java to Kotlin conversion, build migrations and correct use of backend frameworks

PluginExtended access1.1KRepository stars

19 skills for UI, code and copy: the agent decides from project evidence and verifies results rather than making a template.

SkillMinimal access55Repository stars

README in short

The README presents a skill of expert Swift concurrency guidance for any agent that supports the open Agent Skills format. The repository is packaged as a portable Agent Plugin with manifests for Claude Code, Cursor, Codex and pi, and installation is described via skills.sh, the OpenAI plugins directory, the Claude Code plugin, Cursor, Gemini CLI and manual copy. The skill covers choosing concurrency tools, safe race-free code, optimization, Swift 6 migration, testing and Core Data. The material is based on the author's Swift concurrency course, distilled into concise references. MIT licensed.

README badge

Original SKILL.md

---
name: swift-concurrency
description: Diagnose Swift Concurrency issues, refactor callback-based code to async/await, and guide Swift 6 migration when working with tasks, actors, @MainActor, Sendable, data races, thread safety, or concurrency-related compiler and linter warnings.
---
# Swift Concurrency

## Fast Path

Before proposing a fix:

1. Analyze `Package.swift` or `.pbxproj` to determine Swift language mode, strict concurrency level, default isolation, and upcoming features. Do this always, not only for migration work.
2. Capture the exact diagnostic and offending symbol.
3. Determine the isolation boundary: `@MainActor`, custom actor, actor instance isolation, or `nonisolated`.
4. Confirm whether the code is UI-bound or intended to run off the main actor.

Guardrails:

- Do not recommend `@MainActor` as a blanket fix. Justify why the code is truly UI-bound.
- Prefer structured concurrency over unstructured tasks. Use `Task.detached` only with a clear reason.
- If recommending `@preconcurrency`, `@unchecked Sendable`, or `nonisolated(unsafe)`, require a documented safety invariant and a follow-up removal plan.
- Optimize for the smallest safe change. Do not refactor unrelated architecture during migration.

Report a problem