SKILL.md
macOS App Design & Development
Guide for designing and implementing native-feeling, "good Mac citizen" apps: fast, elegant, accessible, and deeply integrated with macOS workflows.
Two Rules That Beat Everything Else
- Prefer system components and conventions over bespoke UI—fastest path to "feels right on Mac"
- If you customize bars, backgrounds, borders, or control chrome: stop and justify it
Quick Reference: Mac Citizen Checklist
| Area |
Requirement |
| Menu Bar |
Standard layout (App/File/Edit/View/Window/Help), ⌘, for Settings |
| Keyboard |
Every primary command reachable via keyboard, standard shortcuts work |
| Windows |
Resize fluidly, support multiple windows, respect fullscreen/minimize |
| Sidebars |
Top-level navigation, scannable items, content extends behind |
| Toolbars |
Group by function/frequency, demote secondary to "more" menu |
| Text |
Use system text components, standard editing behaviors |
| Accessibility |
VoiceOver labels, full keyboard navigation, Reduced Motion support |
Liquid Glass Quick Rules
Do:
- Use for navigation/controls layer (toolbars, sidebars, bars)
- Let system components provide built-in behaviors
Don't:
- Apply to content layer (tables, lists, document content)
- Stack "glass on glass"
App Archetypes
Identify your app type first:
- Document-based: Files as primary units (open/save/duplicate)
- Library + editor: Sidebar lists items, detail in main area
- Utility: Single window, optional menu bar
- Menu-bar app: Lives in menu bar, minimal UI
- Pro tool: Dense, power-user workflows
Deliverables Before Building
- App archetype identified
- Information architecture (sidebar structure, navigation, window model)
- Command map (menus + keyboard shortcuts for every major feature)
- State + data model (persistence, undo/redo, concurrency)
- Accessibility plan (VoiceOver, keyboard, contrast, reduce motion)
Full Reference
For complete design system details, Icon Composer workflow, SF Symbols guidance, evaluation rubrics, and Definition of Done checklist:
See: [references/macos-design-guide.md](references/macos-design-guide.md)
Common Mistakes
| Mistake |
Fix |
| Missing menu bar commands |
Every feature in menus with keyboard shortcuts |
| Settings outside App menu |
Always ⌘, opening from App menu |
| Custom text components |
Use system text for Mac editing ecosystem |
| Toolbar overload |
Demote secondary actions, group by function |
| Glass on content |
Reserve Liquid Glass for navigation layer only |
| Breaking standard shortcuts |
Never override ⌘C, ⌘V, ⌘Z, etc. |
| Single-window only |
Support multiple windows when it benefits workflows |