swift-concurrency

Overview

A Claude Code skill providing expert guidance on Swift Concurrency best practices, patterns, and implementation. It covers modern async/await patterns, actors, tasks, Sendable conformance, and migration to Swift 6, helping developers write safe and performant concurrent code while navigating the complexities of Swift's structured concurrency model.

Key Features

• Swift 6 Migration Support - Analyzes project settings (language mode, strict concurrency checking level, upcoming features) to provide version-appropriate advice for migrating to Swift 6
• Actor Isolation Analysis - Identifies isolation boundaries (@MainActor, custom actor, nonisolated) before proposing fixes, avoiding blanket @MainActor recommendations
• Structured Concurrency First - Prioritizes child tasks and task groups over unstructured tasks, requiring documented justification for Task.detached usage
• Safety Invariant Enforcement - Requires documented safety invariants and follow-up tickets when recommending @preconcurrency, @unchecked Sendable, or nonisolated(unsafe)
• Project Settings Intake - Evaluates SwiftPM and Xcode build settings including SWIFT_STRICT_CONCURRENCY, default actor isolation, and upcoming feature flags before advising

Who is this for?

This skill is designed for Swift developers working with concurrency who need guidance on async/await patterns, actor isolation, and Sendable conformance. It is particularly valuable for teams migrating existing codebases to Swift 6 strict concurrency or resolving data race and thread safety issues in their applications.