macOS Development Expert

Lifecycle Position

Phases 0-1 (Scaffold → Architecture). Start here for new apps (app-planner/ module) and system design (architecture-patterns/ module). Next: load macos-app-design for UI design.

Comprehensive guidance for macOS app development. This skill aggregates specialized modules for different aspects of macOS development.

When This Skill Activates

Use this skill when the user:

• Asks about macOS development best practices
• Wants code review for macOS/Swift projects
• Needs help with SwiftUI, SwiftData, or AppKit
• Is implementing macOS 26 (Tahoe) features
• Wants UI/UX review against HIG
• Needs architecture guidance for macOS apps

Available Modules

Read relevant module files based on the user's needs:

coding-best-practices/

Swift 6+ code quality and modern idioms.

• coding-best-practices/swift-language.md - Modern Swift patterns
• coding-best-practices/modern-concurrency.md - async/await, actors, Sendable
• coding-best-practices/data-persistence.md - SwiftData, UserDefaults, Keychain, actor-based JSON persistence (swift-actor-persistence)
• coding-best-practices/code-organization.md - Project structure and modularity
• coding-best-practices/architecture-principles.md - Clean architecture patterns

architecture-patterns/

Software design and architecture.

• architecture-patterns/solid-detailed.md - SOLID principles with Swift examples
• architecture-patterns/design-patterns.md - Common design patterns
• architecture-patterns/modular-design.md - Modular architecture approaches

swiftdata-architecture/

SwiftData deep dive.

• swiftdata-architecture/schema-design.md - Model design and relationships
• swiftdata-architecture/query-patterns.md - Efficient queries and predicates
• swiftdata-architecture/performance.md - Optimization techniques

macos-tahoe-apis/

macOS 26 specific features.

• macos-tahoe-apis/tahoe-features.md - New macOS 26 capabilities
• macos-tahoe-apis/apple-intelligence.md - AI/ML integration
• macos-tahoe-apis/mlx-framework.md - On-device ML with MLX
• macos-tahoe-apis/continuity.md - Cross-device features
• macos-tahoe-apis/xcode26.md - Xcode 26 tools, agentic coding, and MCP support

macos-capabilities/

Platform integration.

• macos-capabilities/sandboxing.md - App Sandbox and entitlements
• System integration features

appkit-swiftui-bridge/

Hybrid development.

• appkit-swiftui-bridge/nsviewrepresentable.md - Wrapping AppKit views
• State management between frameworks

ui-review-tahoe/

UI/UX review for macOS 26.

• Liquid Glass design system
• HIG compliance checking
• Accessibility review

app-planner/

Project planning and analysis.

• New app architecture planning
• Existing app audits

references/

macOS-specific UI patterns and integration points.

• references/menu-bar.md - Menu bar commands, CommandMenu, CommandGroup, focused menu state
• references/macos-settings.md - Settings scene, tabbed SettingsView, @AppStorage, OpenSettingsAction

How to Use

1. Identify user's need from their question
2. Read relevant module files from subdirectories
3. Apply the guidance to their specific context
4. Reference Apple documentation when needed

Example Workflow

User asks about SwiftData performance:

1. Read swiftdata-architecture/performance.md
2. Read swiftdata-architecture/query-patterns.md if relevant
3. Apply recommendations to their code