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Apple platform development with Swift, SwiftUI, async/await, and performance. Use when working with .swift files, Package.swift, Xcode projects, or building for iOS/macOS/watchOS/visionOS.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Execution trace capture and token baselining. Use when user says trace, extract trace, count tokens, token baseline, or /harness-trace. Not for harness optimization (use harness-mechanic).
Release prep and tagging with pre-flight verification. Use when user says release, tag, ship it, push to production, create release, or bump version. Not for editing a version string outside a release, a lockfile or a changelog entry by hand, and not for reading what changed in a past release: those are ordinary edits, just do them.
Mine LEARNING.md retrospectives across all repos for recurring failure-modes, then propose harness changes (hooks, rules, skills, checklist items) with falsifiable change-contracts. Also runs the doc-gardening pass over the governance docs (stale rules, dead cross-references, skill-table drift). Use when user says learning loop, mine learnings, recurring failures, what should I fix in my process, cross-repo retrospective, doc gardening, stale docs, or run learning-loop. Runs on human schedule, never autonomously. Not for single-project retrospectives (use learning-docs) or trace/token analysis (use harness-mechanic).
Full contractor-mode loop: sub-protocols (LOCALIZE, BENCH-BASELINE, REPRODUCE, DRIFT), review routing by file pattern, blast radius, UAT, parallelism and effort caps, escalation, just-do-it, goal-backed runs. Load it to RUN that loop, once you have an approved plan and are entering step 1, or when a step needs its detail. It is a protocol, not a way to do the work: it never replaces the language, review or planning skill the task itself calls for, and a task small enough to just edit (SKIP_SET) needs none of it. The always-on spine lives in rules/orchestrator-protocol.md. Not for trace capture (harness-trace) or harness optimization (harness-mechanic).
Ruby on Rails with service-oriented architecture, Dry-validation, Sidekiq/Solid Queue, Hotwire. Use for Rails API, Rails services, Rails forms, RSpec, ActiveRecord, Rails migrations. Not for standalone Ruby gems (use ruby skill), and not for judging whether a migration is safe to run in production (that is the database-reviewer agent).
Get three independent second opinions (isolated Claude + isolated Gemini + isolated DeepSeek) on a problem Claude is analyzing. Use when user says second opinion, another perspective, challenge this approach, or asks gemini/deepseek about a decision, approach, or diagnosis. Also invoke on your own initiative, without being asked: on a complex task before planning, after 2 failed root-cause attempts, on a 🔴 decision (rewrite, core logic, security), or when the review loop is stuck below 80 after 2 fix rounds. Gathers context, writes a focused prompt, calls all reviewers in isolated Docker containers, and synthesizes all viewpoints. Not for reviewing code or changes, even phrased as 'ask gemini to review' (use gemini-review).
| name | apple-swift |
| description | Apple platform development with Swift, SwiftUI, async/await, and performance. Use when working with .swift files, Package.swift, Xcode projects, or building for iOS/macOS/watchOS/visionOS. |
| compatibility | Requires Xcode and platform SDKs. Optional: SwiftLint. |
| allowed-tools | ["mcp__acp__Read","mcp__acp__Edit","mcp__acp__Write","mcp__acp__Bash"] |
# Build
xcodebuild -scheme MyApp -sdk iphoneos build
xcodebuild -scheme MyApp -sdk macosx build
# Tests (pick <booted device> from: xcrun simctl list devices | grep Booted)
xcodebuild test -scheme MyApp -destination 'platform=iOS Simulator,name=<booted device>'
# SwiftLint / SPM
swiftlint lint [--fix]
swift build && swift test && swift package resolve
# ast-grep
sg --pattern '@Observable final class $NAME { $$$ }' --lang swift
sg --pattern '@MainActor' --lang swift
See also: _AST_GREP.md, _PATTERNS.md, source-control, references/
See ../_LANG_COMMON.md. Fetch the truth:
swift --version # local toolchain
xcodebuild -version # Xcode version
cat .swift-version 2>/dev/null # pinned toolchain (if present)
grep -E 'swift-tools-version' Package.swift # SPM minimum
curl -s https://api.github.com/repos/swiftlang/swift/releases/latest | jq -r .tag_name # latest upstream
make check && make test-e2e must pass (enforced by the pre-commit-gate hook; see ../_LANG_COMMON.md). What make check expands to for an Apple project:
swift build # compilation check
swift test # unit tests
swiftlint lint --strict # lint (fail on warnings)
swift-format lint --recursive Sources Tests # formatting check
xcodebuild -scheme MyApp test \
-destination 'platform=iOS Simulator,name=<booted device>' # platform tests
Pick <booted device> from xcrun simctl list devices | grep Booted (do not hardcode a simulator model).
| Wrapper | Use |
|---|---|
@State | View-owned values, @Observable |
@Binding | Two-way to parent |
@Bindable | Two-way to @Observable props |
@Environment | System/app values |
@StateObject | View-owned ObservableObject (legacy) |
View property order: @Environment, let, @State/@Binding, computed, init, body, private methods
View sizing: <100 lines = single view; 100-200 = extract subviews; >200 = multiple files; business logic = @Observable VM; network/DB = repository pattern
For NavigationStack, SwiftData, MVVM, and DI patterns, see references/swiftui-patterns.md.
| Error | Fix |
|---|---|
| Main actor isolation | Add @MainActor to class/func |
| Non-isolated access | Mark nonisolated |
| Sendable violation | Add @unchecked Sendable or fix |
| Protocol async | Require async in protocol |
| Closure capture | Use @Sendable closure |
| Use Case | Choice |
|---|---|
| One-shot network | async/await |
| Parallel fetches | async let / TaskGroup |
| Real-time streams | Combine / AsyncStream |
| UI events, debounce | Combine |
NON-NEGOTIABLE: UI updates always on @MainActor. Cross-actor value types must be Sendable. Respect task cancellation: check Task.isCancelled in long-running work.
For MainActor, parallel execution, and actor patterns, see references/concurrency-patterns.md.
MVVM with @Observable: @Observable @MainActor final class VM with private(set) properties, injected service protocols, async load methods with defer { isLoading = false }.
DI: Protocol-based with EnvironmentKey for SwiftUI injection.
Coordinator pattern: For flow-heavy apps, lift navigation state out of views into a Coordinator type owning a NavigationPath (or route enum) and exposing intents.
Testing (Swift Testing): @Suite, @Test, #expect. Parameterized with arguments:. Mock via protocol injection. XCTest still valid where needed (UI tests, legacy targets).
For full code examples, see references/swiftui-patterns.md and references/swift6-patterns.md.
Concurrency: MainActor for UI, Sendable for cross-actor data, task cancellation handled, no data races
SwiftUI: @Observable over ObservableObject where available, NavigationStack over NavigationView, .task over .onAppear + Task, LazyVStack for long lists
CRITICAL: Force unwrap without safety, UI updates off MainActor, data races, retain cycles
HIGH: Legacy ObservableObject when @Observable fits, NavigationView in new code
references/swift6-patterns.md - Strict concurrency migration, Sendable, actors, macrosreferences/swiftui-patterns.md - NavigationStack, SwiftData, MVVM, dependency injectionreferences/concurrency-patterns.md - async/await, TaskGroup, MainActor, actors, AsyncStreamreferences/performance.md - Optimization, Instruments profiling, memory managementOfficial: Swift | SwiftUI | SwiftData
Libraries: TCA | Snapshot Testing | SwiftLint