frostist/swift-human-guidelines

Overview

This skill delivers comprehensive Swift 6 and SwiftUI development guidelines for Apple platforms, including iOS 26, iOS 18, iPadOS, macOS, watchOS, visionOS, and tvOS. It consolidates Apple Human Interface Guidelines, Swift 6 language features, Foundation Models integration, background processing, and cross-platform architecture into actionable recommendations. Use it to design maintainable, high-performance apps that leverage modern concurrency, Apple Intelligence, and platform-specific APIs.

How this skill works

The skill inspects Swift code, SwiftUI views, Xcode project structure, and app architecture patterns to recommend best practices and anti-patterns. It highlights platform-specific APIs (Foundation Models, BGContinuedProcessingTask, Call Translation) and Swift 6 features (Sendable, typed throws, data-race safety) and maps them to concrete implementation patterns. It also provides templates, reference documents, and performance strategies for profiling and optimization.

When to use it

• Starting a new app for any Apple platform (single or universal)
• Architecting cross-platform code sharing and platform-specific UI
• Implementing Apple Intelligence features (Foundation Models, on-device processing)
• Optimizing concurrency, data-race safety, and performance with Swift 6
• Building background processing, call translation, or GPU tasks (iOS 26+)
• Migrating code to Swift 6 and adopting new language features

Best practices

• Adopt MVVM with unidirectional data flow and dependency injection for testability
• Choose appropriate property wrappers: @State, @StateObject, @ObservedObject, @EnvironmentObject, @Binding
• Use async/await and MainActor where appropriate; prefer Sendable types and minimize @Published surface area
• Profile with Instruments, use Lazy stacks for big lists, and provide stable IDs for ForEach
• Maximize shared code (models, services, view models) and use conditional compilation for platform specifics
• Follow Human Interface Guidelines, support Dynamic Type, accessibility, and respect system settings

Example use cases

• Create a universal app sharing models and services across iOS, macOS, and visionOS with platform-specific navigation
• Integrate Foundation Models for on-device summarization, extraction, or classification in iOS 26+
• Implement background continuation using BGContinuedProcessingTask for long-lived, user-initiated work
• Add live call translation using the Call Translation API for multilingual communication apps
• Optimize heavy concurrency paths using Swift 6 synchronization primitives, actors, and Sendable enforcement