WCAG Accessibility Audit

This skill enables AI agents to perform a comprehensive web accessibility evaluation using the Web Content Accessibility Guidelines (WCAG) 2.1 and 2.2 standards, ensuring digital products are usable by people with disabilities.

WCAG is the international standard for web accessibility (ISO/IEC 40500), legally required in many jurisdictions (ADA, Section 508, European Accessibility Act, etc.).

Use this skill to identify accessibility barriers, ensure legal compliance, reach broader audiences, and build inclusive digital experiences.

Combine with "Nielsen Heuristics Audit" for comprehensive usability evaluation or "Don Norman Principles" for human-centered design assessment.

When to Use This Skill

Invoke this skill when:

• Ensuring legal compliance with accessibility laws (ADA, Section 508, EAA)
• Auditing websites or apps for accessibility barriers
• Planning inclusive design improvements
• Preparing for accessibility certifications
• Evaluating vendor products for procurement
• Training teams on accessibility standards
• Conducting pre-launch accessibility reviews

Inputs Required

When executing this audit, gather:

• interface_description: Detailed description (type: website/web app/mobile app, purpose, target users, key features) [REQUIRED]
• urls_or_screenshots: Live URLs (preferred) or screenshots of key pages/screens [OPTIONAL but highly recommended]
• target_conformance_level: A, AA (most common), or AAA [OPTIONAL, defaults to AA]
• specific_concerns: Known accessibility issues or user complaints [OPTIONAL]
• assistive_technologies_used: Screen readers, keyboard-only, voice control, etc. [OPTIONAL]
• wcag_version: 2.1 or 2.2 (defaults to 2.2, latest) [OPTIONAL]

The 4 POUR Principles

WCAG is organized around 4 core principles:

1. Perceivable

Information and user interface components must be presentable to users in ways they can perceive.

Guidelines:

• 1.1 Text Alternatives
• 1.2 Time-based Media
• 1.3 Adaptable
• 1.4 Distinguishable

2. Operable

User interface components and navigation must be operable.

Guidelines:

• 2.1 Keyboard Accessible
• 2.2 Enough Time
• 2.3 Seizures and Physical Reactions
• 2.4 Navigable
• 2.5 Input Modalities

3. Understandable

Information and the operation of user interface must be understandable.

Guidelines:

• 3.1 Readable
• 3.2 Predictable
• 3.3 Input Assistance

4. Robust

Content must be robust enough that it can be interpreted by a wide variety of user agents, including assistive technologies.

Guidelines:

• 4.1 Compatible

Conformance Levels

WCAG defines three levels of conformance:

• Level A: Minimum level (essential accessibility features)
• Level AA: Target level for most organizations (addresses major barriers) ⭐ MOST COMMON
• Level AAA: Highest level (enhanced accessibility, not always achievable for all content)

Legal Requirements: Most laws require Level AA compliance.

Critical Success Criteria (Level A & AA)

Focus on these high-impact criteria:

Perceivable (Critical Criteria)

1.1.1 Non-text Content (A)

• All images, icons, and graphics have meaningful alt text
• Decorative images have empty alt="" or role="presentation"
• Complex images (charts, diagrams) have extended descriptions

1.3.1 Info and Relationships (A)

• Semantic HTML (headings, lists, tables, forms)
• Proper heading hierarchy (h1 → h2 → h3)
• Form labels associated with inputs
• Tables have proper headers

1.3.2 Meaningful Sequence (A)

• Content order makes sense when CSS is disabled
• Reading order matches visual order
• Tab order is logical

1.4.1 Use of Color (A)

• Information not conveyed by color alone
• Color-blind friendly palette
• Alternative indicators (icons, patterns, text)

1.4.3 Contrast (Minimum) (AA)

• Text: 4.5:1 contrast ratio (normal text)
• Large text: 3:1 contrast ratio (18pt+ or 14pt+ bold)
• UI components: 3:1 contrast ratio
• Use tools: WebAIM Contrast Checker

1.4.4 Resize Text (AA)

• Text can be resized to 200% without loss of content or functionality
• No horizontal scrolling at 200% zoom (1280px width)

1.4.10 Reflow (AA) - WCAG 2.1

• Content reflows to 320px width without horizontal scrolling
• No loss of information or functionality
• Responsive design

1.4.11 Non-text Contrast (AA) - WCAG 2.1

• UI components and graphical objects: 3:1 contrast
• Focus indicators, buttons, form controls
• Chart elements, infographics

1.4.12 Text Spacing (AA) - WCAG 2.1

• No loss of content when users adjust:
  • Line height: 1.5× font size
  • Paragraph spacing: 2× font size
  • Letter spacing: 0.12× font size
  • Word spacing: 0.16× font size

Operable (Critical Criteria)

2.1.1 Keyboard (A)

• All functionality available via keyboard
• No keyboard traps (can navigate away)
• Proper focus management
• Test: Navigate entire site with Tab, Enter, Space, Arrow keys

2.1.2 No Keyboard Trap (A)

• Users can move focus away from any component
• Modal dialogs can be closed with Esc
• Focus returns properly after actions

2.1.4 Character Key Shortcuts (A) - WCAG 2.1

• Single character shortcuts can be turned off, remapped, or only active on focus
• Prevents accidental activation

2.4.1 Bypass Blocks (A)

• "Skip to main content" link
• Bypass repetitive navigation
• Landmark regions (header, nav, main, footer)

2.4.2 Page Titled (A)

• Every page has unique, descriptive title
• Title describes page purpose/topic
• Format: "Page Name - Site Name"

2.4.3 Focus Order (A)

• Focus order is logical and intuitive
• Matches visual/reading order
• No unexpected focus jumps

2.4.4 Link Purpose (In Context) (A)

• Link text describes destination
• Avoid "click here", "read more" without context
• Descriptive: "Download Q4 2025 Report (PDF)"

2.4.5 Multiple Ways (AA)

• At least 2 ways to find pages (navigation, search, sitemap)
• Breadcrumbs, related links, table of contents

2.4.6 Headings and Labels (AA)

• Descriptive headings and labels
• Clear form labels
• Logical heading hierarchy

2.4.7 Focus Visible (AA)

• Visible keyboard focus indicator
• Clear outline or highlight
• Minimum 2px, high contrast
• Never remove outline without replacement

2.5.1 Pointer Gestures (A) - WCAG 2.1

• Multi-point or path-based gestures have single-pointer alternative
• Pinch zoom → buttons, swipe → arrow buttons

2.5.2 Pointer Cancellation (A) - WCAG 2.1

• Click/tap actions trigger on up-event (not down)
• Users can cancel by moving pointer away
• Prevents accidental activation

2.5.3 Label in Name (A) - WCAG 2.1

• Visible label text matches accessible name
• Voice control users can activate by visible label

2.5.4 Motion Actuation (A) - WCAG 2.1

• Functionality triggered by device motion has UI alternative
• Shake to undo → has undo button

Understandable (Critical Criteria)

3.1.1 Language of Page (A)

• HTML lang attribute set correctly
• <html lang="en">, <html lang="es">, etc.
• Helps screen readers pronounce correctly

3.1.2 Language of Parts (AA)

• Foreign language phrases marked with lang attribute
• <span lang="fr">Bonjour</span>

3.2.1 On Focus (A)

• Focus doesn't automatically trigger actions
• No automatic form submission on focus
• No unexpected navigation

3.2.2 On Input (A)

• Changing input doesn't cause unexpected actions
• Select dropdown doesn't auto-submit
• Warn before context changes

3.2.3 Consistent Navigation (AA)

• Navigation in same order on every page
• Consistent header/footer/menu placement
• Predictable patterns

3.2.4 Consistent Identification (AA)

• Same icons/buttons have same function throughout
• Search icon always means search
• Consistent labeling

3.3.1 Error Identification (A)

• Errors are clearly identified
• Specific error messages
• Error location is indicated

3.3.2 Labels or Instructions (A)

• Form fields have clear l