Swift Best Practices

What it does

This skill helps you apply modern Swift development best practices, specifically focusing on features introduced in Swift 6 and later versions. It provides guidance on concurrency safety (using async/await, actors, and MainActor), API design principles, code quality guidelines, and migration from Swift 5 to Swift 6. The skill complements the SwiftLens MCP server for semantic-level Swift code analysis within Claude Code.

When to use it

• Writing new Swift code for iOS or macOS applications.
• Reviewing existing Swift code for correctness, safety, and style.
• Implementing concurrency features like async/await and actors.
• Designing Swift APIs and public interfaces.
• Migrating code from Swift 5 to Swift 6.

Key capabilities

• Swift 6+ design patterns and best practices guidance.
• Concurrency strategies (async/await, actors, MainActor).
• API design guidelines and naming conventions.
• Migration assistance from Swift 5 to Swift 6.
• Addresses concurrency warnings, data race issues, or compiler errors related to Sendable/isolation.

Example prompts

• "How should I structure this API using Swift 6 best practices?"
• "Review this code snippet for potential concurrency issues and suggest improvements."
• "What's the recommended approach for migrating this Swift 5 code to Swift 6?"

Tips & gotchas

• Requires setup of a .claude/mcps/swiftlens.json file in your project for integration with the SwiftLens MCP server (see references/swiftlens-mcp-claude-code.md for full instructions).
• This skill is designed to provide design expertise, complementing the runtime analysis provided by SwiftLens.
• Remember that async functions don't automatically run on background threads; explicit thread management may be required.