Builds production-quality, accessible, responsive user-facing UIs. Use when building or modifying interfaces and pages, creating components, implementing layouts, meeting WCAG accessibility requirements, managing state, or when the output needs to look and feel
One skill from addyosmani-agent-skills. Installed with the plugin, it fires itself as you prompt.
Installs just this skill. Get the whole plugin for auto-invocation.
SKILL.md
frontend-ui-engineering.SKILL.md
---name: frontend-ui-engineering
description: Builds production-quality, accessible, responsive user-facing UIs. Use when building or modifying interfaces and pages, creating components, implementing layouts, meeting WCAG accessibility requirements, managing state, or when the output needs to look and feel production-quality rather than AI-generated.
---# Frontend UI Engineering
## Overview
Build production-quality user interfaces that are accessible, performant, and visually polished. The goal is UI that looks like it was built by a design-aware engineer at a top company — not like it was generated by an AI. This means real design system adherence, proper accessibility, thoughtful interaction patterns, and no generic "AI aesthetic."
## When to Use
- Building new UI components or pages
- Modifying existing user-facing interfaces
- Implementing responsive layouts
- Adding interactivity or state management
- Fixing visual or UX issues
## Component Architecture
### File Structure
Colocate everything related to a component:
```
src/components/
TaskList/
TaskList.tsx # Component implementation
TaskList.test.tsx # Tests
TaskList.stories.tsx # Storybook stories (if using)
use-task-list.ts # Custom hook (if complex state)
URL state (searchParams) → Filters, pagination, shareable UI state
Server state (React Query, SWR) → Remote data with caching
Global store (Zustand, Redux) → Complex client state shared app-wide
```
**Avoid prop drilling deeper than 3 levels.** If you're passing props through components that don't use them, introduce context or restructure the component tree.
## Design System Adherence
### Avoid the AI Aesthetic
AI-generated UI has recognizable patterns. Avoid all of them:
| AI Default | Why It Is a Problem | Production Quality |
|---|---|---|
| Purple/indigo everything | Models default to visually "safe" palettes, making every app look identical | Use the project's actual color palette |
| Excessive gradients | Gradients add visual noise and clash with most design systems | Flat or subtle gradients matching the design system |
| Rounded everything (rounded-2xl) | Maximum rounding signals "friendly" but ignores the hierarchy of corner radii in real designs | Consistent border-radius from the design system |
| Generic hero sections | Template-driven layout with no connection to the actual content or user need | Content-first layouts |
| Lorem ipsum-style copy | Placeholder text hides layout problems that real content reveals (length, wrapping, overflow) | Realistic placeholder content |
| Oversized padding everywhere | Equal generous padding destroys visual hierarchy and wastes screen space | Consistent spacing scale |
| Stock card grids | Uniform grids are a layout shortcut that ignores information priority and scanning patterns | Purpose-driven layouts |
| Shadow-heavy design | Layered shadows add depth that competes with content and slows rendering on low-end devices | Subtle or no shadows unless the design system specifies |
### Spacing and Layout
Use a consistent spacing scale. Don't invent values:
```css
/* Use the scale: 0.25rem increments (or whatever the project uses) */
/* Good */ padding: 1rem; /* 16px */
/* Good */ gap: 0.75rem; /* 12px */
/* Bad */ padding: 13px; /* Not on any scale */
/* Bad */ margin-top: 2.3rem; /* Not on any scale */
```
### Typography
Respect the type hierarchy:
```
h1 → Page title (one per page)
h2 → Section title
h3 → Subsection title
body → Default text
small → Secondary/helper text
```
Don't skip heading levels. Don't use heading styles for non-heading content.
### Color
- Use semantic color tokens: `text-primary`, `bg-surface`, `border-default` — not raw hex values
- Ensure sufficient contrast (4.5:1 for normal text, 3:1 for large text)
- Don't rely solely on color to convey information (use icons, text, or patterns too)
## Accessibility (WCAG 2.1 AA)
Every component must meet these standards:
### Keyboard Navigation
```tsx
// Every interactive element must be keyboard accessible
<button onClick={handleClick}>Click me</button> // ✓ Focusable by default
<div onClick={handleClick}>Click me</div> // ✗ Not focusable
<div role="button" tabIndex={0} onClick={handleClick} // ✓ But prefer <button>
onKeyDown={e => {
if (e.key === 'Enter') handleClick();
if (e.key === ' ') e.preventDefault();
}}
onKeyUp={e => {
if (e.key === ' ') handleClick();
}}>
Click me
</div>
```
### ARIA Labels
```tsx
// Label interactive elements that lack visible text
