Swift Concurrency 6 2

Helps you adopt Swift 6.2's new concurrency model where async code stays on the calling actor by default instead of implicitly hopping to background threads. You'll want this when migrating from Swift 6.1 or earlier, especially if you're hitting data race errors that didn't make sense before. The key shift is using isolated conformances for MainActor types and marking functions with @concurrent only when you actually need background execution. The MainActor default inference mode cuts down on boilerplate annotations. If you're building a typical UI-heavy app, this makes concurrency safer by making single-threaded execution the default and parallelism an explicit choice.

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last updated: Aug 21, 2026

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Install

$ npx -y skills add affaan-m/ecc --skill swift-concurrency-6-2 --agent claude-code

Installs into .claude/skills of the current project.

Files

Swift 6.2 Approachable Concurrency

Patterns for adopting Swift 6.2's concurrency model where code runs single-threaded by default and concurrency is introduced explicitly. Eliminates common data-race errors without sacrificing performance.

When to Activate

Migrating Swift 5.x or 6.0/6.1 projects to Swift 6.2
Resolving data-race safety compiler errors
Designing MainActor-based app architecture
Offloading CPU-intensive work to background threads
Implementing protocol conformances on MainActor-isolated types
Enabling Approachable Concurrency build settings in Xcode 26

Core Problem: Implicit Background Offloading

In Swift 6.1 and earlier, async functions could be implicitly offloaded to background threads, causing data-race errors even in seemingly safe code:

// Swift 6.1: ERROR
@MainActor
final class StickerModel {
    let photoProcessor = PhotoProcessor()

    func extractSticker(_ item: PhotosPickerItem) async throws -> Sticker? {
        guard let data = try await item.loadTransferable(type: Data.self) else { return nil }

SKILL.md on GitHub