---

name: check-a11y description: Perform accessibility audit on web pages. Use when users ask to check accessibility, audit WCAG compliance, verify ARIA usage, check color contrast, audit keyboard navigation, or analyze screen reader compatibility. Detects ARIA issues, focus problems, contrast issues, and semantic HTML violations.

Check A11y (Accessibility)

Perform accessibility audit on web pages for WCAG 2.1 compliance.

Quick Start

cd /path/to/html-checker/scripts
bun src/check-a11y.ts <URL>

CLI Options

Option	Short	Default	Description
--verbose	-v	false	Show all checks including passed
--json	-j	false	Output results as JSON
--level	-l	AA	WCAG level (A, AA, AAA)

Checks Performed

Check	WCAG	Severity	Description
Missing lang	3.1.1	Error	HTML has no lang attribute
Skip link missing	2.4.1	Warning	No skip to main content link
Missing landmarks	1.3.1	Warning	No main, nav, header landmarks
Empty links	2.4.4	Error	Links with no accessible name
Empty buttons	4.1.2	Error	Buttons with no accessible name
Missing focus styles	2.4.7	Warning	Interactive elements lack focus indicator
Tabindex > 0	2.4.3	Warning	Positive tabindex disrupts focus order
ARIA hidden focusable	4.1.2	Error	Focusable element inside aria-hidden
Invalid ARIA	4.1.2	Error	Invalid ARIA attributes or values
Missing alt	1.1.1	Error	Images without alt text
Low contrast	1.4.3	Warning	Text contrast below 4.5:1
Auto-playing media	1.4.2	Warning	Audio/video with autoplay

Usage Examples

# Basic audit
bun src/check-a11y.ts https://example.com

# Verbose output
bun src/check-a11y.ts https://example.com --verbose

# AAA level compliance
bun src/check-a11y.ts https://example.com --level AAA

Output Example

Accessibility Audit for https://example.com
WCAG Level: AA

Summary:
  Passed: 18
  Warnings: 5
  Errors: 3

Page Structure:
  [OK] Language declared: lang="en"
  [OK] Main landmark present
  [WARNING] No skip link found
  [WARNING] Multiple nav without labels

Interactive Elements:
  [OK] 45 links checked
  [ERROR] 2 empty links found
  [OK] 12 buttons checked
  [WARNING] 3 buttons rely on icon only

ARIA Usage:
  [OK] Valid ARIA roles
  [ERROR] aria-labelledby references missing ID
  [WARNING] Redundant ARIA on semantic elements

Issues:
  [ERROR  ] Empty link at position 12 (WCAG 2.4.4)
    <a href="/search"><i class="icon-search"></i></a>
  [ERROR  ] Invalid aria-labelledby at position 34 (WCAG 4.1.2)
    <div aria-labelledby="nonexistent-id">
  [WARNING] No skip link (WCAG 2.4.1)
    Add <a href="#main">Skip to content</a>

Score: 72/100 (Level AA)

Recommendations:
  - Add aria-label to icon-only links
  - Fix aria-labelledby references
  - Add skip link for keyboard users

WCAG Quick Reference

Level A (Minimum)

• 1.1.1: Non-text content needs alt text
• 2.1.1: All functionality via keyboard
• 4.1.2: Name, role, value for UI components

Level AA (Recommended)

• 1.4.3: Contrast ratio 4.5:1 minimum
• 2.4.7: Focus visible
• 3.1.2: Language of parts

Level AAA (Enhanced)

• 1.4.6: Contrast ratio 7:1
• 2.4.9: Link purpose from link text alone

Related Files

• Command: plugins/html-checker/commands/check-a11y.md
• Scripts: plugins/html-checker/scripts/src/check-a11y.ts
• Check Forms: plugins/html-checker/skills/check-forms/
• Check Images: plugins/html-checker/skills/check-images/
• Check Links: plugins/html-checker/skills/check-links/