swift-best-practices

# Swift Best Practices Skill

## Overview

Apply modern Swift development best practices focusing on Swift 6+ features, concurrency safety, API design principles, and code quality guidelines for iOS and macOS projects targeting macOS 15.7+.

## When to Use This Skill

Use this skill when:
- Writing new Swift code for iOS or macOS applications
- Reviewing Swift code for correctness, safety, and style
- Implementing Swift concurrency features (async/await, actors, MainActor)
- Designing Swift APIs and public interfaces
- Migrating code from Swift 5 to Swift 6
- Addressing concurrency warnings, data race issues, or compiler errors related to Sendable/isolation
- Working with modern Swift language features introduced in Swift 6 and 6.2

## SwiftLens MCP Integration (Claude Code)

This skill complements **SwiftLens MCP server** for semantic-level Swift code analysis.

**What SwiftLens Provides:**
- 15 tools for semantic Swift analysis using Apple's SourceKit-LSP
- Symbol lookup, cross-file references, type information
- Safe code modification and refactoring
- Compiler-grade understanding of Swift code structure

**What This Skill Provides:**
- Swift 6+ design patterns and best practices
- Concurrency strategies (async/await, actors, MainActor)
- API design guidelines and naming conventions
- Migration guidance (Swift 5 → Swift 6)

**Setup for Claude Code CLI:**

Create `.claude/mcps/swiftlens.json` in your Swift project:

```json
{
  "mcpServers": {
    "swiftlens": {
      "description": "SwiftLens MCP provides semantic Swift analysis via SourceKit-LSP",
      "command": "uvx",
      "args": ["swiftlens"]
    }
  }
}
```

**⚠️ Note**: This is **Claude Code** configuration (not Claude Desktop). See `references/swiftlens-mcp-claude-code.md` for complete setup guide, all 15 tools, index building, and usage examples.

**Workflow**: SwiftLens provides **runtime analysis** (what the code is doing), this skill provides **design expertise** (what the code should be doing).

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