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.
Provides iOS 17+ SwiftUI guidance for modern patterns like @Observable, @Bindable, and MVVM architecture. Triggers when implementing async operations, NavigationStack, UIKit interop, or migrating from ObservableObject.
/plugin marketplace add johnrogers/claude-swift-engineering/plugin install swift-engineering@claude-swift-engineeringThis skill inherits all available tools. When active, it can use any tool Claude has access to.
references/accessibility.mdreferences/async-patterns.mdreferences/composition.mdreferences/environment.mdreferences/migration-guide.mdreferences/mvvm-observable.mdreferences/navigation.mdreferences/observable.mdreferences/performance.mdreferences/state-management.mdreferences/uikit-interop.mdreferences/view-modifiers.mdSwiftUI 17+ removes ObservableObject boilerplate with @Observable, simplifies environment injection with @Environment, and introduces task-based async patterns. The core principle: use Apple's modern APIs instead of reactive libraries.
| Need | Use (iOS 17+) | NOT |
|---|---|---|
| Observable model | @Observable | ObservableObject |
| Published property | Regular property | @Published |
| Own state | @State | @StateObject |
| Passed model (binding) | @Bindable | @ObservedObject |
| Environment injection | environment(_:) | environmentObject(_:) |
| Environment access | @Environment(Type.self) | @EnvironmentObject |
| Async on appear | .task { } | .onAppear { Task {} } |
| Value change | onChange(of:initial:_:) | onChange(of:perform:) |
@Observable for model classes (no @Published needed)@State for view-owned models, @Bindable for passed models.task { } for async work (auto-cancels on disappear)NavigationStack with NavigationPath for programmatic navigation.accessibilityLabel() and .accessibilityHint() to interactive elements| Reference | Load When |
|---|---|
| observable.md | Creating new @Observable model classes |
| state-management.md | Deciding between @State, @Bindable, @Environment |
| environment.md | Injecting dependencies into view hierarchy |
| view-modifiers.md | Using onChange, task, or iOS 17+ modifiers |
| migration-guide.md | Updating iOS 16 code to iOS 17+ |
| mvvm-observable.md | Setting up view model architecture |
| navigation.md | Programmatic or deep-link navigation |
| performance.md | Lists with 100+ items or excessive re-renders |
| uikit-interop.md | Wrapping UIKit components (WKWebView, PHPicker) |
| accessibility.md | VoiceOver, Dynamic Type, accessibility actions |
| async-patterns.md | Loading states, refresh, background tasks |
| composition.md | Reusable view modifiers or complex conditional UI |
Over-using @Bindable for passed models — Creating @Bindable for every property causes unnecessary view reloads. Use @Bindable only for mutable model properties that need two-way binding. Read-only computed properties should use regular properties.
State placement errors — Putting model state in the view instead of a dedicated @Observable model causes view logic to become tangled. Always separate model and view concerns.
NavigationPath state corruption — Mutating NavigationPath incorrectly can leave it in inconsistent state. Use navigationDestination(for:destination:) with proper state management to avoid path corruption.
Missing .task cancellation — .task handles cancellation on disappear automatically, but nested Tasks don't. Complex async flows need explicit cancellation tracking to avoid zombie tasks.
Ignoring environment invalidation — Changing environment values at parent doesn't invalidate child views automatically. Use @Environment consistently and understand when re-renders happen based on observation.
UIKit interop memory leaks — UIViewRepresentable and UIViewControllerRepresentable can leak if delegate cycles aren't broken. Weak references and explicit cleanup are required.
This skill should be used when the user asks to "create a slash command", "add a command", "write a custom command", "define command arguments", "use command frontmatter", "organize commands", "create command with file references", "interactive command", "use AskUserQuestion in command", or needs guidance on slash command structure, YAML frontmatter fields, dynamic arguments, bash execution in commands, user interaction patterns, or command development best practices for Claude Code.
This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "when to use description", "agent examples", "agent tools", "agent colors", "autonomous agent", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
This skill should be used when the user asks to "create a hook", "add a PreToolUse/PostToolUse/Stop hook", "validate tool use", "implement prompt-based hooks", "use ${CLAUDE_PLUGIN_ROOT}", "set up event-driven automation", "block dangerous commands", or mentions hook events (PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification). Provides comprehensive guidance for creating and implementing Claude Code plugin hooks with focus on advanced prompt-based hooks API.