accessibility-patterns
Build inclusive web experiences following WCAG guidelines. Covers semantic HTML, ARIA, keyboard navigation, color contrast, and testing strategies. Triggers on accessibility, a11y, WCAG, screen readers, or inclusive design requests.
Best use case
accessibility-patterns is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
Build inclusive web experiences following WCAG guidelines. Covers semantic HTML, ARIA, keyboard navigation, color contrast, and testing strategies. Triggers on accessibility, a11y, WCAG, screen readers, or inclusive design requests.
Teams using accessibility-patterns should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/accessibility-patterns/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How accessibility-patterns Compares
| Feature / Agent | accessibility-patterns | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
Build inclusive web experiences following WCAG guidelines. Covers semantic HTML, ARIA, keyboard navigation, color contrast, and testing strategies. Triggers on accessibility, a11y, WCAG, screen readers, or inclusive design requests.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Accessibility Patterns
Build for everyone from the start.
## Core Principles (POUR)
| Principle | Meaning | Example |
|-----------|---------|---------|
| **Perceivable** | Users can perceive content | Alt text, captions, contrast |
| **Operable** | Users can interact | Keyboard access, enough time |
| **Understandable** | Users can comprehend | Clear language, predictable |
| **Robust** | Works with assistive tech | Valid HTML, ARIA |
---
## WCAG Levels
| Level | Description | Target |
|-------|-------------|--------|
| A | Minimum | Must have |
| AA | Standard | Industry standard, legal requirement |
| AAA | Enhanced | Nice to have |
**Target Level AA** for most projects.
---
## Semantic HTML
### Use the Right Element
| Instead of | Use |
|------------|-----|
| `<div onclick>` | `<button>` |
| `<span class="link">` | `<a href>` |
| `<div class="header">` | `<header>` |
| `<div class="nav">` | `<nav>` |
| `<div class="main">` | `<main>` |
| `<b>` for emphasis | `<strong>` |
| `<i>` for emphasis | `<em>` |
### Document Structure
```html
<!DOCTYPE html>
<html lang="en">
<head>
<title>Descriptive Page Title</title>
</head>
<body>
<a href="#main" class="skip-link">Skip to main content</a>
<header>
<nav aria-label="Main">
<!-- navigation -->
</nav>
</header>
<main id="main">
<h1>Page Title</h1>
<!-- Only one h1 per page -->
<article>
<h2>Section</h2>
<h3>Subsection</h3>
</article>
</main>
<aside aria-label="Related content">
<!-- sidebar -->
</aside>
<footer>
<!-- footer content -->
</footer>
</body>
</html>
```
### Heading Hierarchy
```
h1 - Page title (one per page)
h2 - Major sections
h3 - Subsections
h4 - Sub-subsections
Never skip levels (h1 → h3)
```
---
## Images & Media
### Alt Text
```html
<!-- Informative image -->
<img src="chart.png" alt="Bar chart showing sales increased 40% in Q4">
<!-- Decorative image -->
<img src="decorative-border.png" alt="" role="presentation">
<!-- Complex image -->
<figure>
<img src="complex-diagram.png" alt="System architecture diagram">
<figcaption>
Detailed description of the system architecture...
</figcaption>
</figure>
<!-- Image as link -->
<a href="/products">
<img src="product.jpg" alt="View our products">
</a>
```
### Alt Text Guidelines
| Image Type | Alt Text Strategy |
|------------|-------------------|
| Informative | Describe content and function |
| Decorative | Empty alt="" |
| Functional | Describe the action |
| Complex | Brief alt + longer description |
| Text in image | Include all text |
### Video & Audio
```html
<!-- Video with captions -->
<video controls>
<source src="video.mp4" type="video/mp4">
<track kind="captions" src="captions.vtt" srclang="en" label="English">
<track kind="descriptions" src="descriptions.vtt" srclang="en" label="Audio descriptions">
</video>
<!-- Audio with transcript -->
<audio controls>
<source src="podcast.mp3" type="audio/mpeg">
</audio>
<a href="transcript.html">Read transcript</a>
```
---
## Forms
### Labels
```html
<!-- Explicit label (preferred) -->
<label for="email">Email address</label>
<input type="email" id="email" name="email">
<!-- Implicit label -->
<label>
Email address
<input type="email" name="email">
</label>
<!-- Required fields -->
<label for="name">
Name <span aria-hidden="true">*</span>
<span class="sr-only">(required)</span>
</label>
<input type="text" id="name" required aria-required="true">
```
### Error Handling
```html
<div role="alert" aria-live="polite">
<p>Please fix the following errors:</p>
<ul>
<li><a href="#email">Email is required</a></li>
</ul>
</div>
<label for="email">Email</label>
<input
type="email"
id="email"
aria-invalid="true"
aria-describedby="email-error"
>
<span id="email-error" class="error">Please enter a valid email address</span>
```
### Form Groups
```html
<fieldset>
<legend>Shipping Address</legend>
<label for="street">Street</label>
<input type="text" id="street">
<label for="city">City</label>
<input type="text" id="city">
</fieldset>
```
---
## Keyboard Navigation
### Focus Management
```css
/* Never remove focus outline without replacement */
:focus {
outline: 2px solid #005fcc;
outline-offset: 2px;
}
/* Custom focus style */
:focus-visible {
outline: 3px solid #005fcc;
outline-offset: 2px;
}
/* Hide outline for mouse users */
:focus:not(:focus-visible) {
outline: none;
}
```
### Tab Order
```html
<!-- Natural tab order follows DOM order -->
<!-- Use tabindex only when necessary -->
<button>First</button>
<button>Second</button>
<button>Third</button>
<!-- tabindex="0" - adds to tab order -->
<div tabindex="0" role="button">Custom interactive element</div>
<!-- tabindex="-1" - focusable via JS, not tab -->
<div tabindex="-1" id="modal">Modal content</div>
<!-- Never use tabindex > 0 -->
```
### Skip Links
```html
<a href="#main" class="skip-link">Skip to main content</a>
<style>
.skip-link {
position: absolute;
top: -40px;
left: 0;
padding: 8px;
background: #000;
color: #fff;
z-index: 100;
}
.skip-link:focus {
top: 0;
}
</style>
```
### Keyboard Patterns
| Component | Keys |
|-----------|------|
| Buttons | Enter, Space |
| Links | Enter |
| Menus | Arrows, Enter, Escape |
| Tabs | Arrows, Tab |
| Modals | Tab (trapped), Escape to close |
---
## ARIA
### When to Use ARIA
1. First, use semantic HTML
2. Then, add ARIA if needed
3. "No ARIA is better than bad ARIA"
### Common ARIA Patterns
```html
<!-- Live regions (for dynamic content) -->
<div aria-live="polite">Content updates will be announced</div>
<div aria-live="assertive">Urgent updates interrupt</div>
<!-- Expanded/collapsed -->
<button aria-expanded="false" aria-controls="menu">Menu</button>
<ul id="menu" hidden>...</ul>
<!-- Current page -->
<nav>
<a href="/" aria-current="page">Home</a>
<a href="/about">About</a>
</nav>
<!-- Busy state -->
<div aria-busy="true">Loading...</div>
<!-- Hidden from AT -->
<span aria-hidden="true">👍</span>
<!-- Labels -->
<button aria-label="Close">×</button>
<nav aria-label="Main navigation">...</nav>
<section aria-labelledby="section-heading">
<h2 id="section-heading">Section Title</h2>
</section>
```
### ARIA Roles
```html
<!-- Landmarks -->
<div role="banner">Header</div>
<div role="navigation">Nav</div>
<div role="main">Main</div>
<div role="complementary">Sidebar</div>
<div role="contentinfo">Footer</div>
<!-- Widgets -->
<div role="button">Custom button</div>
<div role="dialog" aria-modal="true">Modal</div>
<div role="tablist">Tabs</div>
<div role="alert">Error message</div>
```
---
## Color & Contrast
### Contrast Requirements
| Text Size | Level AA | Level AAA |
|-----------|----------|-----------|
| Normal text (<18px) | 4.5:1 | 7:1 |
| Large text (≥18px bold, ≥24px) | 3:1 | 4.5:1 |
| UI components | 3:1 | - |
### Color Independence
```html
<!-- Don't rely on color alone -->
<!-- Bad -->
<span style="color: red">Error</span>
<!-- Good -->
<span style="color: red">
⚠️ Error: <span class="error-text">Please enter a valid email</span>
</span>
```
### Testing Tools
- WebAIM Contrast Checker
- Chrome DevTools color picker
- Stark (Figma plugin)
- axe DevTools
---
## Testing
### Automated Testing
```javascript
// Using jest-axe
import { axe, toHaveNoViolations } from 'jest-axe';
expect.extend(toHaveNoViolations);
it('should have no accessibility violations', async () => {
const { container } = render(<MyComponent />);
const results = await axe(container);
expect(results).toHaveNoViolations();
});
```
### Manual Testing Checklist
- [ ] Navigate entire page with keyboard only
- [ ] Test with screen reader (VoiceOver, NVDA)
- [ ] Check color contrast
- [ ] Zoom to 200% - still usable?
- [ ] Disable CSS - still understandable?
- [ ] Check all images have alt text
- [ ] Verify form labels and errors
- [ ] Test focus visibility
- [ ] Check heading structure
### Screen Reader Testing
| OS | Screen Reader | Browser |
|----|---------------|---------|
| macOS | VoiceOver | Safari |
| Windows | NVDA | Firefox |
| Windows | JAWS | Chrome |
| Mobile | TalkBack | Chrome |
| iOS | VoiceOver | Safari |
---
## Common Patterns
### Modal Dialog
```html
<div
role="dialog"
aria-modal="true"
aria-labelledby="dialog-title"
aria-describedby="dialog-desc"
>
<h2 id="dialog-title">Confirm Action</h2>
<p id="dialog-desc">Are you sure you want to proceed?</p>
<button>Cancel</button>
<button>Confirm</button>
</div>
```
Focus management:
1. Move focus to modal on open
2. Trap focus inside modal
3. Return focus to trigger on close
### Tabs
```html
<div role="tablist" aria-label="Settings">
<button role="tab" aria-selected="true" aria-controls="panel-1" id="tab-1">
General
</button>
<button role="tab" aria-selected="false" aria-controls="panel-2" id="tab-2">
Security
</button>
</div>
<div role="tabpanel" id="panel-1" aria-labelledby="tab-1">
General settings content
</div>
<div role="tabpanel" id="panel-2" aria-labelledby="tab-2" hidden>
Security settings content
</div>
```
---
## References
- `references/wcag-checklist.md` - Full WCAG 2.1 checklist
- `references/aria-patterns.md` - Common ARIA patterns
- `references/testing-tools.md` - Testing tool setupRelated Skills
advanced-patterns
Advanced T-SQL patterns and techniques for SQL Server. Use this skill when: (1) User needs help with CTEs or recursive queries, (2) User asks about APPLY operator, (3) User wants MERGE or OUTPUT clause help, (4) User works with temporal tables, (5) User needs In-Memory OLTP guidance, (6) User asks about advanced grouping (ROLLUP, CUBE, GROUPING SETS).
advanced-js-mocking-patterns
Advanced mocking patterns for Jest and Vitest including module mocking, spies, and fake timers. PROACTIVELY activate for: (1) Module mocking, (2) Partial mocking with spies, (3) Mock lifecycle management, (4) Fake timers for time-dependent code, (5) Complex mock implementations. Triggers: "jest.mock", "vi.mock", "spyOn", "fakeTimers", "mockImplementation", "mockReturnValue", "mock lifecycle"
Advanced GetX Patterns
Advanced GetX features including Workers, GetxService, SmartManagement, GetConnect, GetSocket, bindings composition, and testing patterns
patterns/adapter
Adapter (Wrapper) Pattern pattern for C development
ActiveRecord Query Patterns
Complete guide to ActiveRecord query optimization, associations, scopes, and PostgreSQL-specific patterns. Use this skill when writing database queries, designing model associations, creating migrations, optimizing query performance, or debugging N+1 queries and grouping errors.
Action Cable & WebSocket Patterns
Real-time WebSocket features with Action Cable in Rails. Use when: (1) Building real-time chat, (2) Live notifications/presence, (3) Broadcasting model updates, (4) WebSocket authorization. Trigger keywords: Action Cable, WebSocket, real-time, channels, broadcasting, stream, subscriptions, presence, cable
accessibility
Build WCAG 2.1 AA compliant websites with semantic HTML, proper ARIA, focus management, and screen reader support. Includes color contrast (4.5:1 text), keyboard navigation, form labels, and live regions. Use when implementing accessible interfaces, fixing screen reader issues, keyboard navigation, or troubleshooting "focus outline missing", "aria-label required", "insufficient contrast".
accessibility-wcag
Build accessible web applications following WCAG 2.1/2.2 guidelines with proper semantic HTML, ARIA attributes, keyboard navigation, screen reader support, and inclusive design. Use when implementing ARIA labels and roles, ensuring keyboard navigation, supporting screen readers, providing text alternatives for images, managing focus, creating accessible forms, building inclusive UI components, testing with accessibility tools, meeting WCAG compliance levels, or designing for users with disabilities.
accessibility-validation
Validate digital outputs for compliance with accessibility standards (e.g., WCAG, Section 508). Use when reviewing reports, dashboards, documents, or interfaces from pilot projects to identify and remediate accessibility barriers.
accessibility-ux-audit
Audit and enhance accessibility and UX across all pages and components.
accessibility-testing
WCAG 2.2 compliance testing, screen reader validation, and inclusive design verification. Use when ensuring legal compliance (ADA, Section 508), testing for disabilities, or building accessible applications for 1 billion disabled users globally.
accessibility-tester
Expert accessibility tester specializing in WCAG compliance, inclusive design, and universal access. Masters screen reader compatibility, keyboard navigation, and assistive technology integration with focus on creating barrier-free digital experiences.