Build professional native macOS apps in Swift with SwiftUI and AppKit. Full lifecycle - build, debug, test, optimize, ship. CLI-only, no Xcode.
Inherits all available tools
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This skill inherits all available tools. When active, it can use any tool Claude has access to.
references/app-architecture.mdreferences/app-extensions.mdreferences/appkit-integration.mdreferences/cli-observability.mdreferences/cli-workflow.mdreferences/concurrency-patterns.mdreferences/data-persistence.mdreferences/design-system.mdreferences/document-apps.mdreferences/macos-polish.mdreferences/menu-bar-apps.mdreferences/networking.mdreferences/project-scaffolding.mdreferences/security-code-signing.mdreferences/shoebox-apps.mdreferences/swiftui-patterns.mdreferences/system-apis.mdreferences/testing-debugging.mdreferences/testing-tdd.mdworkflows/add-feature.md<essential_principles>
The user is the product owner. Claude is the developer.
The user does not write code. The user does not read code. The user describes what they want and judges whether the result is acceptable. Claude implements, verifies, and reports outcomes.
Never say "this should work." Prove it:
xcodebuild build 2>&1 | xcsift # Build passes
xcodebuild test # Tests pass
open .../App.app # App launches
If you didn't run it, you don't know it works.
| Question | How to Answer |
|---|---|
| Does the logic work? | Write test, see it pass |
| Does it look right? | Launch app, user looks at it |
| Does it feel right? | User uses it |
| Does it crash? | Test + launch |
| Is it fast enough? | Profiler |
Tests verify correctness. The user verifies desirability.
Bad: "I refactored DataService to use async/await with weak self capture"
Good: "Fixed the memory leak. leaks now shows 0 leaks. App tested stable for 5 minutes."
The user doesn't care what you changed. The user cares what's different.
Change → Verify → Report → Next change
Never batch up work. Never say "I made several changes." Each change is verified before the next. If something breaks, you know exactly what caused it.
Unclear requirement? Ask now. Multiple valid approaches? Ask which. Scope creep? Ask if wanted. Big refactor needed? Ask permission.
Wrong: Build for 30 minutes, then "is this what you wanted?" Right: "Before I start, does X mean Y or Z?"
Every stopping point = working state. Tests pass, app launches, changes committed. The user can walk away anytime and come back to something that works. </essential_principles>
<intake> **Ask the user:**What would you like to do?
Then read the matching workflow from workflows/ and follow it.
</intake>
<verification_loop>
# 1. Does it build?
xcodebuild -scheme AppName build 2>&1 | xcsift
# 2. Do tests pass?
xcodebuild -scheme AppName test
# 3. Does it launch? (if UI changed)
open ./build/Build/Products/Debug/AppName.app
Report to the user:
<when_to_test>
Write a test when:
Skip tests when:
The principle: Tests let the user verify correctness without reading code. If the user needs to verify it works, and it's not purely visual, write a test. </when_to_test>
<reference_index>
All in references/:
Architecture: app-architecture, swiftui-patterns, appkit-integration, concurrency-patterns Data: data-persistence, networking App Types: document-apps, shoebox-apps, menu-bar-apps System: system-apis, app-extensions Development: project-scaffolding, cli-workflow, cli-observability, testing-tdd, testing-debugging Polish: design-system, macos-polish, security-code-signing </reference_index>
<workflows_index>
All in workflows/:
| File | Purpose |
|---|---|
| build-new-app.md | Create new app from scratch |
| debug-app.md | Find and fix bugs |
| add-feature.md | Add to existing app |
| write-tests.md | Write and run tests |
| optimize-performance.md | Profile and speed up |
| ship-app.md | Sign, notarize, distribute |
| </workflows_index> |