swift-concurrency
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.
npx skills add AvdLee/Swift-Concurrency-Agent-Skill --skill swift-concurrency --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# 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. When spawning unstructured tasks, inspect the synchronous prefix (everything before the first `await`): start on `@MainActor` only when that prefix truly needs main-actor access; otherwise use `Task { @concurrent in ... }` and hop back with `MainActor.run` only after the suspension. A trivial non-main line (for example, `print`) followed by main-actor work in the same prefix is not a reason to use `@concurrent`. For delayed retries, timers, and backoff tasks, separate the waiting from the UI mutation. The sleep often belongs off the main actor even when the final state update belongs on it. Project settings that change concurrency behavior: | Setting | SwiftPM (`Package.swift`) | Xcode (`.pbxproj`) | |--
- Fast Path
- Quick Fix Mode
- Common Diagnostics
- When Quick Fixes Fail
- Smallest Safe Fixes
- Concurrency Tool Selection
- Common Scenarios
- Task entry isolation
- Swift 6 Migration Quick Guide
- Migration Validation Loop
- Reference Router
- Verification Checklist
What does the swift-concurrency skill do?
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.
How do I install it?
Run `npx skills add AvdLee/Swift-Concurrency-Agent-Skill --skill swift-concurrency --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From AvdLee/Swift-Concurrency-Agent-Skill, a repository with 1,608 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.