swift-engineering

You are an expert in prompt engineering, specializing in optimizing AI code assistant instructions. Your task is to analyze and improve the instructions for Claude Code. Follow these steps carefully:

description: Resume work from a previous session snapshot. Reads the snapshot file and then deletes it when done.

description: Asks Claude to generate a snapshot summary for a future session. Writes it to file. It can then be read by the `resume-snapshot` command.

Isolates expensive Swift code search operations to preserve main context. Delegates all exploratory 'where is X', 'find Y', 'locate Z' queries to prevent 10-50K tokens of grep noise from polluting conversation. Returns only final results with high-confidence locations. Use this agent INSTEAD of running grep/glob directly when you don't know where Swift code is located.

Plan Swift features with architecture decisions, file structure, and implementation strategy. Use PROACTIVELY when starting any new Swift feature, before implementation begins.

Review Swift/iOS code for quality, security, performance, and HIG compliance. Use after implementation, before testing.

Generate and maintain documentation — project README, package READMEs, and inline code comments. Use after feature completion or for documentation updates.

Implement vanilla Swift code — models, services, networking, persistence. Use when the plan specifies vanilla Swift (not TCA) architecture.

Migrate legacy Swift patterns to modern best practices — async/await, modern APIs, SwiftUI. Use for legacy code modernization.

Create unit and integration tests using Swift Testing framework. Use after implementation is complete.

Analyze UI mockups, screenshots, or descriptions to plan SwiftUI implementation. Use when starting from a visual design or UI description before feature planning.

Implement SwiftUI views following Apple HIG guidelines. Use after core/TCA implementation is complete.

Design TCA (The Composable Architecture) feature architectures — state, actions, dependencies, navigation. Use when the plan specifies TCA and detailed architecture design is needed.

Implement TCA (The Composable Architecture) features — reducers, actions, state, dependencies. Use when the TCA design is complete and implementation is needed.

Use when building features with TCA (The Composable Architecture), structuring reducers, managing state, handling effects, navigation, or testing TCA features. Covers @Reducer, Store, Effect, TestStore, reducer composition, and TCA patterns.

Use when implementing on-device AI with Apple's Foundation Models framework (iOS 26+), building summarization/extraction/classification features, or using @Generable for type-safe structured output.

Use when encountering unfamiliar import statements, exploring dependency APIs, or when user asks "what's import X" or "what does X do". Generates on-demand API documentation for Swift package dependencies.

Use when writing raw SQL with GRDB, complex joins across 4+ tables, window functions, ValueObservation for reactive queries, or dropping down from SQLiteData for performance. Direct SQLite access for iOS/macOS with type-safe queries and migrations.

Use when adding haptic feedback for user confirmations (button presses, toggles, purchases), error notifications, or custom tactile patterns (Core Haptics). Covers UIFeedbackGenerator and CHHapticEngine patterns.

Use when implementing iOS 26 features (Liquid Glass, new SwiftUI APIs, WebView, Chart3D), deploying iOS 26+ apps, or supporting backward compatibility with iOS 17/18.

Use when designing iOS interfaces, implementing accessibility (VoiceOver, Dynamic Type), handling dark mode, ensuring adequate touch targets, providing animation/haptic feedback, or requesting user permissions. Apple Human Interface Guidelines for iOS compliance.

Use when implementing internationalization (i18n), String Catalogs, pluralization, or right-to-left layout support. Covers modern localization workflows with Xcode String Catalogs and LocalizedStringKey patterns.

Use when writing async/await code, enabling strict concurrency, fixing Sendable errors, migrating from completion handlers, managing shared state with actors, or using Task/TaskGroup for concurrency.

Use when working with SQLiteData library (@Table, @FetchAll, @FetchOne macros) for SQLite persistence, queries, writes, migrations, or CloudKit private database sync.

Use when implementing in-app purchases, StoreKit 2 subscriptions, consumables, non-consumables, or transaction handling. Covers testing-first workflow with .storekit configuration, StoreManager architecture, and transaction verification.

Use when debugging NavigationStack issues (not responding, unexpected pops, crashes), build failures (SPM resolution, "No such module", hanging builds), or memory problems (retain cycles, leaks, deinit not called). Systematic diagnostic workflows for iOS/macOS.

Use when implementing Network.framework connections (NWConnection, NetworkConnection), debugging connection failures, migrating from sockets/URLSession streams, or handling network transitions. Covers UDP/TCP patterns, structured concurrency networking (iOS 26+), and common anti-patterns.

Swift code style conventions for clean, readable code. Use when writing Swift code to ensure consistent formatting, naming, organization, and idiomatic patterns.

Use when writing tests with Swift Testing (@Test,

Use when implementing gesture composition (simultaneous, sequenced, exclusive), adaptive layouts (ViewThatFits, AnyLayout, size classes), or choosing architecture patterns (MVVM vs TCA vs vanilla, State-as-Bridge). Covers advanced SwiftUI patterns beyond basic views.

Use when implementing iOS 17+ SwiftUI patterns: @Observable/@Bindable, MVVM architecture, NavigationStack, lazy loading, UIKit interop, accessibility (VoiceOver/Dynamic Type), async operations (.task/.refreshable), or migrating from ObservableObject/@StateObject.