Agent Skills: Swift Core

Swift Core

Swift 6 fundamentals shared across all Apple platforms.

Agent Workflow (MANDATORY)

Before ANY implementation, use TeamCreate to spawn 3 agents:

1. fuse-ai-pilot:explore-codebase - Analyze existing Swift patterns
2. fuse-ai-pilot:research-expert - Verify latest Swift 6 docs via Context7/Exa
3. mcp__apple-docs__search_apple_docs - Check Swift concurrency patterns

After implementation, run fuse-ai-pilot:sniper for validation.

Overview

When to Use

• Implementing async/await, actors, Sendable
• Designing app architecture (MVVM, Clean Architecture)
• Writing async tests with XCTest
• Localizing with String Catalogs
• Profiling with Instruments

Why Swift Core

| Feature | Benefit | |---------|---------| | Actors | Thread-safe shared state without locks | | @Observable | Simple reactive state (replaces ObservableObject) | | String Catalogs | Automatic localization with Xcode 15+ | | Instruments | Built-in performance profiling |

Key Concepts

Concurrency (Swift 6)

Modern async/await with strict concurrency checking. Actors provide thread-safe state, Sendable marks safe types.

Architecture

MVVM with @Observable is the recommended pattern. Clean Architecture for complex apps with domain separation.

Testing

XCTest with native async/await support. No need for expectations with async tests.

Internationalization

String Catalogs are mandatory. All user-facing text must be localized.

Performance

Profile with Instruments. Use lazy loading, avoid heavy work in view body.

Reference Guide

| Need | Reference | |------|-----------| | Async/await, actors, Sendable | concurrency.md | | MVVM, Clean Architecture, DI | architecture.md | | XCTest, async tests, mocking | testing.md | | String Catalogs, localization | i18n.md | | Instruments, optimization | performance.md |

Best Practices

1. Actors for shared state - Prefer actors over classes with locks
2. @Observable over ObservableObject - Simpler, better performance
3. Structured concurrency - async/await, no completion handlers
4. String Catalogs - ALL user-facing text must be localized
5. Profile in Release - Always profile with -O optimization
6. Value types - Prefer structs over classes