mobile-app-ux
Mobile app UX/UI best practices for smartphone interfaces. Use for designing touch-friendly interfaces, mobile navigation patterns, gesture handling, and optimizing user experience on small screens. Triggers on requests for mobile UX, app design, touch interfaces, mobile patterns, or smartphone UI best practices.
What this skill does
# Mobile App UX Best Practices
## Touch Target Guidelines
| Element | Minimum Size | Recommended | Spacing |
|---------|-------------|-------------|---------|
| Buttons | 44×44px | 48×48px | 8px between |
| Icons | 24×24px | 24×24px + 44px touch area | 12px between |
| List items | 44px height | 48-56px height | No gap needed |
| Form inputs | 44px height | 48px height | 16px between |
```css
.touch-target {
min-height: 44px;
min-width: 44px;
padding: var(--space-3);
}
/* Expand touch area without visual change */
.icon-button {
position: relative;
}
.icon-button::after {
content: '';
position: absolute;
inset: -8px;
}
```
## ✅ Do's
### Navigation
- Bottom navigation for 3-5 primary actions
- Keep most important actions within thumb reach
- Use clear, recognizable icons with labels
- Provide visual feedback on active state
- Support swipe gestures for natural navigation
### Content
- Prioritize content over chrome (UI elements)
- Use progressive disclosure - show essentials first
- Lazy load content below the fold
- Provide pull-to-refresh for dynamic content
- Show skeleton screens, not spinners
### Forms
- Use appropriate keyboard types (email, tel, number)
- Show inline validation, not after submit
- Provide autocomplete where possible
- Group related fields visually
- Save form progress automatically
### Feedback
- Immediate visual response to all touches
- Haptic feedback for important actions
- Clear loading states with progress indication
- Confirmation for destructive actions
- Undo option instead of "Are you sure?"
## ❌ Don'ts
### Navigation
- ❌ Hamburger menus for primary navigation
- ❌ Deep navigation hierarchies (>3 levels)
- ❌ Small, closely spaced tap targets
- ❌ Gestures without visual affordances
- ❌ Hiding essential actions in menus
### Content
- ❌ Horizontal scrolling for content
- ❌ Tiny text (<16px for body copy)
- ❌ Low contrast text on images
- ❌ Auto-playing video with sound
- ❌ Interstitials blocking content
### Forms
- ❌ Required fields without indication
- ❌ Generic error messages
- ❌ Disabling zoom on inputs
- ❌ Dropdowns for <5 options (use radio)
- ❌ Multi-step forms without progress indicator
### Interaction
- ❌ Double-tap to activate
- ❌ Hover-dependent interactions
- ❌ Precise targeting requirements
- ❌ Long press without alternative
- ❌ Blocking the UI during operations
## Thumb Zone Design
```
┌─────────────────────┐
│ Hard to reach │ ← Secondary actions, menu
│ │
├─────────────────────┤
│ Natural reach │ ← Content, scrollable area
│ │
├─────────────────────┤
│ Easy reach │ ← Primary actions, nav
└─────────────────────┘
```
```css
/* Bottom-anchored primary actions */
.primary-actions {
position: fixed;
bottom: 0;
left: 0;
right: 0;
padding: var(--space-4);
padding-bottom: env(safe-area-inset-bottom, var(--space-4));
}
```
## Component Patterns
### Bottom Sheet
```tsx
interface BottomSheetProps {
isOpen: boolean;
onClose: () => void;
children: ReactNode;
}
export const BottomSheet: FC<BottomSheetProps> = ({ isOpen, onClose, children }) => (
<>
{isOpen && <div className="overlay" onClick={onClose} />}
<div className={cn('bottom-sheet', isOpen && 'bottom-sheet--open')}>
<div className="bottom-sheet__handle" />
{children}
</div>
</>
);
```
### Swipeable Card
```tsx
export const SwipeableCard: FC<Props> = ({ onSwipeLeft, onSwipeRight, children }) => {
const handlers = useSwipeable({
onSwipedLeft: onSwipeLeft,
onSwipedRight: onSwipeRight,
trackMouse: false,
});
return <div {...handlers}>{children}</div>;
};
```
## Performance Checklist
- [ ] First Contentful Paint < 1.8s
- [ ] Time to Interactive < 3.8s
- [ ] Images optimized and lazy-loaded
- [ ] Animations at 60fps
- [ ] No layout shifts during load
- [ ] Works offline (PWA)
## Accessibility
- Use semantic HTML (`<button>`, `<nav>`, `<main>`)
- Support screen readers (aria-labels)
- Ensure 4.5:1 color contrast minimum
- Support text scaling up to 200%
- Never disable pinch-to-zoom
Related in Design
contribute
IncludedLocal-only OSS contribution command center. Auto-refreshes the user's in-flight PR and issue state on invoke so conversations start with full context — no need to brief Claude on what's in flight. Helps the user find issues to contribute to on GitHub, builds per-repo dossiers of what each upstream expects (CLA, DCO, branch convention, AI policy, draft-first, review bots, issue templates), runs deterministic gates before any external action so AI-assisted contributions don't reach maintainers as slop. State is markdown-only: candidate files at ~/.contribute-system/candidates/, repo dossiers at ~/.contribute-system/research/, append-only event log at ~/.contribute-system/log.jsonl. No database, no cloud calls. Use when the user asks about their PRs / issues / contributions, wants to find new work to take on, claim an issue, build/refresh a repo's dossier, or draft a Design Issue or PR. Trigger with "/contribute", "what's my PR status", "find a contribution", "claim issue X", "draft a Design Issue for Y", "refresh dossier for Z".
architectural-analysis
IncludedUser-triggered deep architectural analysis of a codebase or scoped subtree across eight modes — information architecture, data flow, integration points, UI surfaces, interaction patterns, data model, control flow, and failure modes. This skill should be used when the user asks to "diagram this codebase," "map the architecture," "show the data flow," "give me an ERD," "trace control flow," "find the integration points," "verify the layout pattern," "audit the UX architecture," or any similar request whose primary deliverable is mermaid diagrams plus cited reports under docs/architecture/. Dispatches haiku/sonnet sub-agents in parallel for per-mode exploration, then verifies every citation mechanically before any node lands in a diagram. Not for one-off prose explanations of code (use code-explanation) or for high-level system design from scratch (use system-design).
mcp
IncludedModel Context Protocol (MCP) server development and tool management. Languages: Python, TypeScript. Capabilities: build MCP servers, integrate external APIs, discover/execute MCP tools, manage multi-server configs, design agent-centric tools. Actions: create, build, integrate, discover, execute, configure MCP servers/tools. Keywords: MCP, Model Context Protocol, MCP server, MCP tool, stdio transport, SSE transport, tool discovery, resource provider, prompt template, external API integration, Gemini CLI MCP, Claude MCP, agent tools, tool execution, server config. Use when: building MCP servers, integrating external APIs as MCP tools, discovering available MCP tools, executing MCP capabilities, configuring multi-server setups, designing tools for AI agents.
react-native-skia
IncludedDesign, build, debug, and optimise high-polish animated graphics in React Native or Expo using @shopify/react-native-skia, Reanimated, and Gesture Handler. Use when the user wants canvas-driven UI, shaders, paths, rich text, image filters, sprite fields, Skottie, video frames, snapshots, web CanvasKit setup, or performance tuning for custom motion-heavy elements such as loaders, hero art, cards, charts, progress indicators, particle systems, or gesture-driven surfaces. Also use when the user asks for fluid, glow, glass, blob, parallax, 60fps/120fps, or GPU-friendly animated effects in React Native, even if they do not explicitly say "Skia". Do not use for ordinary form/layout work with standard views.
plaid
IncludedProduct Led AI Development — guides founders from idea to launched product. Six capabilities: Idea (discover a product idea), Validate (pressure-test the idea against fatal flaws, problem reality, competition, and 2-week MVP feasibility), Plan (vision intake + document generation), Design (translate image references into a design.md spec), Launch (go-to-market strategy), and Build (roadmap execution). Use when someone says "PLAID", "plaid idea", "help me find an idea", "product idea", "idea from my business", "idea from my expertise", "plaid validate", "validate my idea", "pressure-test", "is this idea good", "find fatal flaws", "validate the problem", "plan a product", "define my vision", "generate a PRD", "product strategy", "plaid design", "design from image", "translate image to design", "create design.md", "extract design tokens", "plaid launch", "go-to-market", "launch plan", "GTM strategy", "launch playbook", "plaid build", "build the app", "start building", or "execute the roadmap".
nextjs-framer-motion-animations
IncludedAdds production-safe Motion for React or Framer Motion animations to Next.js apps, including reveal, hover and tap micro-interactions, whileInView, stagger, AnimatePresence, layout and layoutId transitions, reorder, scroll-linked UI, and lightweight route-content transitions. Use when the user asks to add, refactor, or debug Motion or Framer Motion in App Router or Pages Router codebases, especially around server/client boundaries, reduced motion, LazyMotion, bundle size, hydration, or route transitions. Avoid for GSAP-style timelines, WebGL or 3D scenes, heavy scroll storytelling, or CSS-only effects unless Motion is explicitly requested.