Testing & Debugging Skills

iOS app architecture expert skill covering MVVM with @Observable, Clean Architecture, The Composable Architecture (TCA), modular architecture with SPM, Repository pattern, Coordinator/Router pattern, Dependency Injection (Factory, Environment), error handling patterns, and protocol-oriented programming. Use this skill when the user architects an iOS app, designs feature modules, sets up project structure, implements MVVM/Clean/TCA patterns, creates repositories or use cases, or asks about iOS code organization. Triggers on: architecture, MVVM, clean architecture, TCA, composable architecture, repository pattern, coordinator, dependency injection, DI, view model, use case, interactor, modular, SPM package, feature module, project structure, folder structure, app architecture, design pattern, unidirectional data flow, reducer, store, or any iOS app structure discussion.

Swift Concurrency expert skill covering async/await, structured concurrency (Task, TaskGroup), actors and @MainActor, Sendable protocol and checking, AsyncSequence/AsyncStream, continuations for bridging callback APIs, Swift 6 strict concurrency mode, and common concurrency patterns (debouncing, throttling, actor-based shared state, background processing). Use this skill whenever the user writes concurrent Swift code, works with async/await, actors, or Sendable, migrates to Swift 6 concurrency, or needs to handle background work and thread safety. Triggers on: async, await, Task, TaskGroup, actor, @MainActor, Sendable, @Sendable, concurrency, AsyncSequence, AsyncStream, continuation, withCheckedContinuation, nonisolated, GlobalActor, Swift 6, strict concurrency, data race, thread safety, background task, parallel, concurrent, dispatch queue migration, or any Swift concurrency question.

iOS data persistence expert skill covering SwiftData (@Model, ModelContainer, @Query, Predicate, migrations, CloudKit), Core Data (NSPersistentContainer, NSFetchRequest, batch operations, CloudKit), UserDefaults/@AppStorage, FileManager (app sandbox directories), Keychain for sensitive data, iCloud key-value storage, and SQLite/GRDB. Use this skill whenever the user needs to persist data, create data models, query databases, handle migrations, sync with iCloud, or choose a storage strategy. Triggers on: SwiftData, Core Data, @Model, @Query, Predicate, ModelContainer, NSManagedObject, NSFetchRequest, UserDefaults, @AppStorage, FileManager, documents directory, Keychain, iCloud sync, SQLite, GRDB, persistence, database, migration, schema, data model, fetch, save, delete, storage, cache, offline, or any iOS data storage question.

Build, review, or improve networking code in iOS/macOS apps using URLSession with async/await, structured concurrency, and modern Swift patterns. Use when working with REST APIs, downloading files, uploading data, WebSocket connections, pagination, retry logic, request middleware, caching, background transfers, or network reachability monitoring. Also use when handling HTTP requests, API clients, network error handling, or data fetching in Swift apps.

Expert SwiftUI development skill for building iOS apps. Covers layout system (VStack/HStack/ZStack/Grid/LazyStacks), state management (@State/@Binding/@Observable/@Environment), navigation (NavigationStack/NavigationSplitView), animations (springs/transitions/matchedGeometryEffect/PhaseAnimator/KeyframeAnimator), lists and scroll views, sheets/alerts/popovers, custom ViewModifiers and ViewBuilders, SwiftUI lifecycle, performance optimization, and UIKit interop. Use this skill whenever the user builds SwiftUI views, layouts, navigation, animations, or asks about SwiftUI state management, view lifecycle, or performance. Triggers on any SwiftUI-related work including: SwiftUI, View, @State, @Binding, @Observable, NavigationStack, List, ScrollView, sheet, alert, animation, transition, ViewModifier, @ViewBuilder, GeometryReader, LazyVStack, TabView, toolbar, searchable, AsyncImage, or any iOS UI development with Swift.

Invoke any time a user is writing iOS/Swift tests or asking why tests behave a certain way — including XCTest versus Swift Testing (@Test/expect) choices, async ViewModel tests with @Observable or @Published, snapshot testing across device sizes, mocking protocols for dependency injection, setUp/tearDown lifecycle issues, tests that fail on CI but pass locally, flaky async tests, testing VIPER/TCA/MVVM architectures, and coverage gaps on error paths. The trigger is user intent: they are trying to verify, assert, or validate iOS/Swift behavior in a test context, whether they use the word 'testing' or not.

iOSアプリのセキュリティレビュー。OWASP Mobile Top 10、App Transport Security、Keychain使用をチェック。Use when: セキュリティ、脆弱性、認証、Keychain、ATS…