swift

name	swift
description	Swift language and concurrency: API design, SOLID, protocols, generics, typed errors, SPM package structure, naming, async/await, actors, Sendable, tasks, AsyncSequence, Swift 6 strict concurrency and data-race safety. Use when writing, reviewing, or architecting Swift code, fixing concurrency issues, or migrating to Swift 6. Not for SwiftUI views (use swiftui), platform APIs (use apple-platforms), GPU work (use metal), or security reviews (use apple-secure-coding).
allowed-tools	["Read","Glob","Grep"]

Swift

Swift language and concurrency guidance that applies everywhere Swift runs (Apple platforms, Linux, server, embedded).

Each domain has a _guide.md — load it first for rules and checklists, then load detailed references on demand.

Swift Language

API design, type safety, protocols, generics, typed errors, SPM packages, naming, architecture

Load: references/swift/_guide.md

Topic	Reference
SOLID, composition, DI	references/swift/architecture.md
Value types, generics, errors	references/swift/type-system.md
SPM layout, Package.swift	references/swift/package-structure.md
Naming, file structure	references/swift/naming-conventions.md
Doc comments, MARK	references/swift/documentation.md
Deep patterns: some vs any, COW, property wrappers, anti-patterns, UIKit interop	references/swift/deep-patterns.md
Memory layout, ARC traffic, CoW internals, cache-aware Swift	references/swift/memory-layout-performance.md

Swift Concurrency

async/await, actors, tasks, Sendable, Swift 6 migration, data races, @MainActor

Load: references/concurrency/_guide.md

Topic	Reference
async/await syntax, patterns	references/concurrency/async-await-basics.md
Tasks, groups, cancellation	references/concurrency/tasks.md
Actors, @MainActor, reentrancy, Mutex	references/concurrency/actors.md
Sendable, region isolation	references/concurrency/sendable.md
AsyncSequence, AsyncStream	references/concurrency/async-sequences.md
Async algorithm patterns	references/concurrency/async-algorithms.md
Threading, suspension, isolation	references/concurrency/threading.md
Core Data integration	references/concurrency/core-data.md
Concurrency lint rules	references/concurrency/linting.md
Swift 6 migration strategy	references/concurrency/migration.md
Async testing patterns	references/concurrency/testing.md
Profiling async code	references/concurrency/performance.md
Retain cycles in tasks	references/concurrency/memory-management.md
QoS, scheduling, cooperative pool contract, blocking hazards	references/concurrency/scheduling-qos.md
Terminology glossary	references/concurrency/glossary.md

Review Checklist (Quick)

• SOLID, DRY, value types, final classes
• No force unwraps, no Any, no empty catches
• Typed errors, guard-early pattern
• Naming follows Swift API Design Guidelines
• Access control starts at private
• some preferred over any unless heterogeneous collection needed
• Structured concurrency preferred; no Task {} in inits or computed properties
• Sendable conformance at isolation boundaries; cancellation handled

Related Skills

Need	Skill
Primary-source Apple/Swift docs lookup (MCP/CLI)	apple-docs
SwiftUI views, state, design system	swiftui
iOS 26-era platform APIs (Liquid Glass, Foundation Models)	apple-platforms
SDK 27 SwiftUI changes	swiftui-whats-new-27
Metal shaders, GPU compute	metal
Keychain, CryptoKit, threat modeling	apple-secure-coding
Unsafe-pointer review, ownership invariants	memory-safety
Cache/scheduling theory behind the Swift specifics	hardware-runtime
Test strategy and TDD	testing
Building/testing via Xcode CLI and agents	xcode-agentic

Project Conventions (Dynamic)

Before applying generic guidance, check for project-specific conventions:

1. ./.claude/skills/*/references/**/conventions.md (project-level skills)
2. ~/.claude/skills/project-conventions/ (user-level project template)

When found, project conventions take precedence for testing patterns, module structure, naming (domain terminology), and DI patterns. The generic guidance in this skill applies universally; project conventions layer on top.

Sources

This skill incorporates knowledge from Apple documentation, Swift Evolution proposals, and established Swift community engineering practices.