Astro Components Skill
Purpose
Provides reusable UI components. Does NOT handle sections, layouts, or business logic.
Scope
| ✅ Use For | ❌ NOT For |
|---|---|
| Marketing sites | Web apps |
| Lead gen pages | Dashboards |
| Service websites | E-commerce carts |
Core Rules
- •All styling via design-tokens — No hardcoded colors/spacing
- •Token missing = build error — Never fallback to arbitrary values
- •Mobile-first — Base styles for mobile,
md:for larger - •44px minimum touch targets — All interactive elements
- •Zero external dependencies — Pure Astro + Tailwind only
Semantic HTML Rules
| Element | Use | Never |
|---|---|---|
<button> | Actions, toggles | <div onclick> |
<a> | Navigation | <span onclick> |
<input> | Form data | Contenteditable div |
Rule: If it does something → <button>. If it goes somewhere → <a>.
Component Variants
Fixed variants only. Claude cannot invent new variants.
| Component | Allowed Variants |
|---|---|
| Button | primary, secondary, outline, ghost |
| Card | default, elevated, outlined |
| Badge | default, success, warning, error, info |
| Alert | info, success, warning, error |
New variant needed? → Update this skill first, then use.
Props Pattern (All Components)
typescript
interface Props {
variant?: 'primary' | 'secondary'; // Explicit union, no string
size?: 'sm' | 'md' | 'lg'; // Fixed sizes only
class?: string; // Allow extension
// ... component-specific
}
const { variant = 'primary', size = 'md' } = Astro.props;
JavaScript Rules
| Allowed | Forbidden |
|---|---|
client:visible islands | Inline onclick |
| Astro actions | <script> in component |
Separate .ts files | Any DOM manipulation |
Exception: None. If JS needed, use island architecture.
Icon Handling
typescript
// If icon name not found → render nothing + console.warn
const path = icons[name];
if (!path) {
console.warn(`Icon "${name}" not found`);
return null;
}
No silent failures. Missing icon = visible warning in dev.
Form Components
| Rule | Requirement |
|---|---|
| Label | Always visible, linked via for |
| Placeholder | Hint only, never replaces label |
| Error | Below input, role="alert" |
| Required | Visual indicator (*) + required attr |
Component Boundaries
Components must NOT:
- •Fetch data
- •Format/transform data
- •Access global state
- •Import other components (except Icon)
- •Contain business logic
Rule: Component receives props → renders UI. Nothing else.
File Structure
code
src/components/ui/ ├── Button.astro ├── Input.astro ├── Card.astro ├── Badge.astro ├── Alert.astro ├── Icon.astro └── index.ts
Forbidden
- •❌ External UI libraries
- •❌ Hardcoded colors/spacing
- •❌ Touch targets under 44px
- •❌ Missing focus states
- •❌ Inline JavaScript
- •❌ Inventing new variants
- •❌ Silent failures
References
- •button.md — Button component code
- •input.md — Input component code
- •card.md — Card component code
- •icon.md — Icon component + full icon list
Definition of Done
- • Uses design-tokens only
- • All interactive: focus states + 44px touch
- • TypeScript Props interface
- • No inline JavaScript
- • Tested on mobile 375px