A11Y Ally

/a11y-ally - Comprehensive Accessibility Audit

THIS IS AN LLM-POWERED SKILL

The value of this skill is Claude's intelligence, not just running automated tools:

IF YOU SKIP THE LLM ANALYSIS, THIS SKILL HAS NO VALUE.

EXECUTION MODEL

CLAUDE EXECUTES ALL STEPS WITHOUT STOPPING.

Do NOT wait for user prompts between steps. Execute the full pipeline:

1. Data Collection: Run multi-tool scan (axe-core, pa11y, Lighthouse) via Bash
2. LLM Analysis: Read results and analyze context for each violation
3. Vision Pipeline: If videos detected → download → extract frames → Read each frame → describe
4. Intelligent Remediation: Generate context-specific fixes using your reasoning
5. Generate Reports: Write all output files to docs/accessibility-scans/{page-slug}/

WRONG:

Claude: "I found 5 violations. Should I analyze them?"
User: "Yes"
Claude: "I see a video. Should I run the video pipeline?"
User: "Yes"

RIGHT:

Claude: [Runs scan] → [Analyzes violations] → [Downloads video] → [Extracts frames] →
        [Reads each frame with Vision] → [Generates captions] → [Writes all files]
        "Audit complete. Generated 4 files in docs/accessibility-scans/example/"

STEP 1: BROWSER AUTOMATION - Content Fetching

Uses the qe-browser fleet skill as the browser engine. qe-browser wraps Vibium (WebDriver BiDi, 10MB Go binary) and provides the QE primitives we rely on. See .claude/skills/qe-browser/SKILL.md.

1.1: PRIMARY — qe-browser via Vibium CLI

# Navigate
vibium go "$TARGET_URL"
vibium wait load

# Capture accessibility tree without visual render
vibium a11y-tree --json > /tmp/a11y-work/tree.json

# Screenshot for Vision pipeline
vibium screenshot -o /tmp/a11y-work/page.png --full-page

If Vibium MCP tools are registered (mcp__vibium__*), prefer them; otherwise shell out to the vibium binary installed by aqe init.

1.2: Run axe-core + WCAG assertions via qe-browser

# Inject axe-core via vibium eval and collect violations
vibium eval --stdin <<'EOF'
const s = document.createElement('script');
s.src = 'https://cdnjs.cloudflare.com/ajax/libs/axe-core/4.10.2/axe.min.js';
document.head.appendChild(s);
await new Promise(r => s.onload = r);
const results = await axe.run();
JSON.stringify({ violations: results.violations.length, issues: results.violations });
EOF

# Enforce: no critical a11y violations + no failed network requests
node .claude/skills/qe-browser/scripts/assert.js --checks '[
  {"kind": "no_console_errors"},
  {"kind": "no_failed_requests"},
  {"kind": "selector_visible", "selector": "main, [role=main]"}
]'

1.3: FALLBACK — pa11y + Lighthouse (when axe alone is insufficient)

# Only use when you need the extra rulesets, not as the primary path
pa11y "$TARGET_URL" --reporter json > /tmp/a11y-work/pa11y.json
lighthouse "$TARGET_URL" --only-categories=accessibility --output=json --output-path=/tmp/a11y-work/lighthouse.json --chrome-flags="--headless"

Why we dropped playwright-extra + puppeteer-extra-plugin-stealth from the primary path:

• 300MB+ of Node deps vs Vibium's 10MB binary
• Redundant: Vibium uses WebDriver BiDi which is less fingerprintable than raw CDP
• Simpler: one tool instead of a cascade

1d: PARALLEL MULTI-PAGE AUDIT (Optional)

For auditing multiple URLs simultaneously, use parallel execution:

// /tmp/a11y-work/parallel-audit.js
const { chromium } = require('playwright-extra');
const stealth = require('puppeteer-extra-plugin-stealth')();
const { AxeBuilder } = require('@axe-core/playwright');

chromium.use(stealth);

const MAX_CONCURRENT = 6;  // Maximum parallel auditors

async function auditUrl(browser, url) {
  const context = await browser.newContext();
  const page = await context.newPage();

  try {
    await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 60000 });
    await page.waitForTimeout(2000);

    const axeResults = await new AxeBuilder({ page })
      .withTags(['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa', 'wcag22aa'])
      .analyze();

    return { url, success: true, violations: axeResults.violations };
  } catch (error) {
    return { url, success: false, error: error.message };
  } finally {
    await context.close();
  }
}

async function parallelAudit(urls) {
  const browser = await chromium.launch({ headless: true });
  const results = [];

  // Process in chunks of MAX_CONCURRENT
  for (let i = 0; i < urls.length; i += MAX_CONCURRENT) {
    const chunk = urls.slice(i, i + MAX_CONCURRENT);
    console.log(`Auditing batch ${Math.floor(i/MAX_CONCURRENT) + 1}: ${chunk.length} URLs`);

    const chunkResults = await Promise.all(
      chunk.map(url => auditUrl(browser, url))
    );
    results.push(...chunkResults);
  }

  await browser.close();
  return results;
}

// Usage: node parallel-audit.js url1 url2 url3 ...
const urls = process.argv.slice(2);
if (urls.length > 0) {
  parallelAudit(urls).then(results => {
    console.log(JSON.stringify(results, null, 2));
  });
}

Usage for multi-page audit:

node parallel-audit.js https://example.com https://example.com/about https://example.com/contact

1e: SITE CRAWL MODE (Optional)

For comprehensive site audits, crawl and audit all pages:

// /tmp/a11y-work/crawl-audit.js
async function crawlAndAudit(startUrl, maxPages = 50) {
  const browser = await chromium.launch({ headless: true });
  const visited = new Set();
  const toVisit = [startUrl];
  const results = [];
  const baseUrl = new URL(startUrl).origin;

  while (toVisit.length > 0 && results.length < maxPages) {
    const url = toVisit.shift();
    if (visited.has(url)) continue;
    visited.add(url);

    console.log(`[${results.length + 1}/${maxPages}] Auditing: ${url}`);

    const context = await browser.newContext();
    const page = await context.newPage();

    try {
      await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 30000 });

      // Extract same-domain links for crawling
      const links = await page.evaluate((base) => {
        return [...document.querySelectorAll('a[href]')]
          .map(a => a.href)
          .filter(href => href.startsWith(base) && !href.includes('#'))
          .filter(href => !href.match(/\.(pdf|jpg|png|gif|css|js)$/i));
      }, baseUrl);

      // Add new links to queue
      links.forEach(link => {
        if (!visited.has(link) && !toVisit.includes(link)) {
          toVisit.push(link);
        }
      });

      // Run accessibility audit
      const axeResults = await new AxeBuilder({ page })
        .withTags(['wcag2a', 'wcag2aa', 'wcag22aa'])
        .analyze();

      results.push({ url, violations: axeResults.violations });
    } catch (e) {
      results.push({ url, error: e.message });
    }

    await context.close();
  }

  await browser.close();
  return { pagesAudited: results.length, results };
}

// Usage: node crawl-audit.js https://example.com 50
const [startUrl, maxPages] = process.argv.slice(2);
crawlAndAudit(startUrl, parseInt(maxPages) || 50).then(r => console.log(JSON.stringify(r, null, 2)));

STEP 2: COMPREHENSIVE WCAG SCAN (Multi-Tool, Parallel, Resilient)

IMPORTANT: This step uses THREE accessibility testing tools for maximum coverage:

• axe-core: Industry standard, excellent for ARIA and semantic issues
• pa11y: Strong on contrast, links, and HTML validation
• Lighthouse: Google's accessibility scoring with performance correlation

Combined detection rate is ~15% higher than any single tool.

2.0: RESILIENCE ARCHITECTURE (v7.0 Enhancement)

Key improvements over v6.0:

Coverage by tools succeeded:

• 3/3 tools: ~95% detection (optimal)
• 2/3 tools: ~85% detection (good)
• 1/3 tools: ~70% detection (acceptable)
• 0/3 tools: FAIL - retry with different strategy

2.1: Run Multi-Tool Analysis (PARALLEL + RESILIENT)

Create and run /tmp/a11y-work/multi-tool-scan.js:

const { chromium } = require('playwright-extra');
const stealth = require('puppeteer-extra-plugin-stealth')();
const { AxeBuilder } = require('@axe-core/playwright');
const pa11y = require('pa11y');
const lighthouse = require('lighthouse').default || require('lighthouse');
const { launch: launchChrome } = require('chrome-launcher');
const fs = require('fs');

chromium.use(stealth);

const TARGET_URL = process.argv[2] || 'TARGET_URL';
const OUTPUT_FILE = '/tmp/a11y-work/scan-results.json';
const SYSTEM_CHROMIUM = '/usr/bin/chromium';

// ========== RESILIENCE UTILITIES ==========

// Timeout wrapper - wraps any promise with a timeout
function withTimeout(promise, ms, name) {
  return Promise.race([
    promise,
    new Promise((_, reject) =>
      setTimeout(() => reject(new Error(`${name} timed out after ${ms}ms`)), ms)
    )
  ]);
}

// Retry wrapper - retries with exponential backoff
async function withRetry(fn, name, maxRetries = 3, baseDelay = 2000) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      return await fn();
    } catch (error) {
      const isLastAttempt = attempt === maxRetries;
      console.log(`[${name}] Attempt ${attempt}/${maxRetries} failed: ${error.message}`);
      if (isLastAttempt) throw error;
      const delay = baseDelay * Math.pow(2, attempt - 1); // Exponential backoff
      console.log(`[${name}] Retrying in ${delay}ms...`);
      await new Promise(r => setTimeout(r, delay));
    }
  }
}

// Sleep utility
const sleep = (ms) => new Promise(r => setTimeout(r, ms));

// Progressive output - append results as they arrive
function progressiveOutput(tool, data) {
  console.log(`\n=== ${tool.toUpperCase()} COMPLETE ===`);
  console.log(JSON.stringify(data, null, 2));

  // Append to results file for progressive access
  try {
    let results = {};
    if (fs.existsSync(OUTPUT_FILE)) {
      results = JSON.parse(fs.readFileSync(OUTPUT_FILE, 'utf8'));
    }
    results[tool] = data;
    results.lastUpdated = new Date().toISOString();
    fs.writeFileSync(OUTPUT_FILE, JSON.stringify(results, null, 2));
  } catch (e) { /* ignore file errors */ }
}

// ========== TOOL RUNNERS ==========

// TOOL 1: Axe-core (with page info extraction)
async function runAxeCore(url) {
  console.log('[axe-core] Starting...');
  const browser = await chromium.launch({
    headless: true,
    executablePath: SYSTEM_CHROMIUM,
    args: [
      '--no-sandbox',
      '--disable-setuid-sandbox',
      '--disable-dev-shm-usage',
      '--disable-blink-features=AutomationControlled'
    ]
  });

  const context = await browser.newContext({
    userAgent: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
    locale: 'en-US',
    viewport: { width: 1920, height: 1080 }
  });

  const page = await context.newPage();

  try {
    // Use domcontentloaded (faster, more reliable than networkidle)
    await page.goto(url, { waitUntil: 'domcontentloaded', timeout: 30000 });

    // Random delay to appear human
    await sleep(2000 + Math.random() * 2000);

    // Try to dismiss cookie banners
    try {
      const cookieSelectors = [
        'button:has-text("Accept")', 'button:has-text("Akzeptieren")',
        'button:has-text("Alle akzeptieren")', '[data-testid="cookie-accept"]',
        '#onetrust-accept-btn-handler', '.cookie-consent-accept'
      ];
      for (const selector of cookieSelectors) {
        const btn = await page.$(selector);
        if (btn) { await btn.click(); await sleep(500); break; }
      }
    } catch (e) { /* ignore cookie errors */ }

    // Run axe-core analysis
    const axeResults = await new AxeBuilder({ page })
      .withTags(['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa', 'wcag22aa'])
      .analyze();

    // Extract comprehensive page info
    const pageInfo = await page.evaluate(() => ({
      title: document.title,
      url: window.location.href,
      lang: document.documentElement.lang,
      images: {
        total: document.querySelectorAll('img').length,
        withAlt: document.querySelectorAll('img[alt]').length,
        withoutAlt: document.querySelectorAll('img:not([alt])').length,
        emptyAlt: document.querySelectorAll('img[alt=""]').length
      },
      headings: {
        h1: Array.from(document.querySelectorAll('h1')).map(h => h.textContent.trim().slice(0,60)),
        h2: document.querySelectorAll('h2').length,
        h3: document.querySelectorAll('h3').length,
        total: document.querySelectorAll('h1,h2,h3,h4,h5,h6').length
      },
      forms: {
        total: document.querySelectorAll('form').length,
        inputs: document.querySelectorAll('input, select, textarea').length,
        buttons: document.querySelectorAll('button').length
      },
      links: { total: document.querySelectorAll('a').length },
      aria: {
        ariaLabels: document.querySelectorAll('[aria-label]').length,
        roles: document.querySelectorAll('[role]').length
      },
      landmarks: {
        main: document.querySelectorAll('main').length,
        nav: document.querySelectorAll('nav').length,
        header: document.querySelectorAll('header').length,
        footer: document.querySelectorAll('footer').length
      },
      media: {
        videos: document.querySelectorAll('video').length,
        iframes: document.querySelectorAll('iframe').length,
        videoUrls: Array.from(document.querySelectorAll('video')).map(v => {
          const src = v.src || (v.querySelector('source') ? v.querySelector('source').src : '');
          return {
            src: src,
            hasCaptions: !!v.querySelector('track[kind="captions"]')
          };
        })
      }
    }));

    const violations = axeResults.violations.map(v => ({
      tool: 'axe-core',
      id: v.id,
      impact: v.impact,
      description: v.description,
      help: v.help,
      helpUrl: v.helpUrl,
      tags: v.tags,
      nodeCount: v.nodes.length,
      nodes: v.nodes.slice(0, 5).map(n => ({
        html: n.html.slice(0, 200),
        target: n.target,
        failureSummary: n.failureSummary
      }))
    }));

    return {
      success: true,
      pageInfo,
      violations,
      passesCount: axeResults.passes.length
    };
  } finally {
    await context.close();
    await browser.close();
  }
}

// TOOL 2: Pa11y
async function runPa11y(url) {
  console.log('[pa11y] Starting...');
  const results = await pa11y(url, {
    standard: 'WCAG2AA',
    timeout: 45000,
    wait: 2000,
    chromeLaunchConfig: {
      executablePath: SYSTEM_CHROMIUM,
      args: ['--no-sandbox', '--disable-setuid-sandbox', '--disable-dev-shm-usage']
    }
  });

  const violations = results.issues.map(issue => ({
    tool: 'pa11y',
    id: issue.code,
    impact: issue.type === 'error' ? 'serious' : issue.type === 'warning' ? 'moderate' : 'minor',
    description: issue.message,
    selector: issue.selector,
    context: (issue.context || '').slice(0, 200)
  }));

  return { success: true, violations, total: results.issues.length };
}

// TOOL 3: Lighthouse
async function runLighthouse(url) {
  console.log('[lighthouse] Starting...');
  const chrome = await launchChrome({
    chromePath: SYSTEM_CHROMIUM,
    chromeFlags: ['--headless', '--no-sandbox', '--disable-gpu', '--disable-dev-shm-usage']
  });

  try {
    const result = await lighthouse(url, {
      port: chrome.port,
      onlyCategories: ['accessibility'],
      output: 'json'
    });

    const lhr = result.lhr;
    const score = Math.round(lhr.categories.accessibility.score * 100);
    const violations = Object.values(lhr.audits)
      .filter(audit => audit.score !== null && audit.score < 1)
      .map(audit => ({
        tool: 'lighthouse',
        id: audit.id,
        impact: audit.score === 0 ? 'critical' : audit.score < 0.5 ? 'serious' : 'moderate',
        score: audit.score,
        description: audit.title
      }));

    return { success: true, score, violations };
  } finally {
    await chrome.kill();
  }
}

// ========== MAIN: PARALLEL EXECUTION WITH GRACEFUL DEGRADATION ==========

(async () => {
  console.log('=== MULTI-TOOL ACCESSIBILITY SCAN (v7.0 PARALLEL + RESILIENT) ===');
  console.log('Target:', TARGET_URL);
  console.log('Strategy: Promise.allSettled with per-tool timeouts\n');

  const startTime = Date.now();

  // Run ALL tools in PARALLEL with individual timeouts
  const [axeResult, pa11yResult, lighthouseResult] = await Promise.allSettled([
    withTimeout(
      withRetry(() => runAxeCore(TARGET_URL), 'axe-core', 2, 3000),
      60000, 'axe-core'
    ),
    withTimeout(
      withRetry(() => runPa11y(TARGET_URL), 'pa11y', 2, 3000),
      60000, 'pa11y'
    ),
    withTimeout(
      withRetry(() => runLighthouse(TARGET_URL), 'lighthouse', 2, 3000),
      90000, 'lighthouse'
    )
  ]);

  // ========== PROCESS RESULTS (Graceful Degradation) ==========
  const results = {
    url: TARGET_URL,
    timestamp: new Date().toISOString(),
    duration: `${((Date.now() - startTime) / 1000).toFixed(1)}s`,
    toolsSucceeded: 0,
    toolsFailed: 0,
    pageInfo: null,
    violations: [],
    byTool: {}
  };

  // Process axe-core results
  if (axeResult.status === 'fulfilled') {
    results.toolsSucceeded++;
    results.pageInfo = axeResult.value.pageInfo;
    results.violations.push(...axeResult.value.violations);
    results.byTool['axe-core'] = {
      success: true,
      count: axeResult.value.violations.length,
      passes: axeResult.value.passesCount
    };
    progressiveOutput('axe-core', axeResult.value);
  } else {
    results.toolsFailed++;
    results.byTool['axe-core'] = { success: false, error: axeResult.reason.message };
    console.log('\n[axe-core] FAILED:', axeResult.reason.message);
  }

  // Process pa11y results
  if (pa11yResult.status === 'fulfilled') {
    results.toolsSucceeded++;
    results.violations.push(...pa11yResult.value.violations);
    results.byTool['pa11y'] = {
      success: true,
      count: pa11yResult.value.violations.length
    };
    progressiveOutput('pa11y', pa11yResult.value);
  } else {
    results.toolsFailed++;
    results.byTool['pa11y'] = { success: false, error: pa11yResult.reason.message };
    console.log('\n[pa11y] FAILED:', pa11yResult.reason.message);
  }

  // Process lighthouse results
  if (lighthouseResult.status === 'fulfilled') {
    results.toolsSucceeded++;
    results.violations.push(...lighthouseResult.value.violations);
    results.byTool['lighthouse'] = {
      success: true,
      score: lighthouseResult.value.score,
      count: lighthouseResult.value.violations.length
    };
    progressiveOutput('lighthouse', lighthouseResult.value);
  } else {
    results.toolsFailed++;
    results.byTool['lighthouse'] = { success: false, error: lighthouseResult.reason.message };
    console.log('\n[lighthouse] FAILED:', lighthouseResult.reason.message);
  }

  // ========== DEDUPLICATE VIOLATIONS ==========
  const seen = new Set();
  const uniqueViolations = [];
  for (const v of results.violations) {
    const key = (v.description || '').toLowerCase().slice(0, 50);
    if (!seen.has(key)) {
      seen.add(key);
      uniqueViolations.push(v);
    }
  }
  results.uniqueViolations = uniqueViolations;
  results.totalUnique = uniqueViolations.length;

  // ========== FINAL OUTPUT ==========
  console.log('\n' + '='.repeat(60));
  console.log('=== SCAN COMPLETE ===');
  console.log('='.repeat(60));
  console.log(`Tools succeeded: ${results.toolsSucceeded}/3`);
  console.log(`Tools failed: ${results.toolsFailed}/3`);
  console.log(`Duration: ${results.duration}`);
  console.log(`Total unique violations: ${results.totalUnique}`);

  if (results.toolsSucceeded === 0) {
    console.log('\n⚠️  ALL TOOLS FAILED - Consider:');
    console.log('   1. Site may have strong bot protection');
    console.log('   2. Try Vibium MCP browser instead');
    console.log('   3. Check network connectivity');
  } else if (results.toolsSucceeded < 3) {
    console.log(`\n⚠️  Partial coverage (${results.toolsSucceeded}/3 tools) - Results still usable`);
  } else {
    console.log('\n✅ Full coverage achieved (3/3 tools)');
  }

  console.log('\n=== PAGE INFO ===');
  console.log(JSON.stringify(results.pageInfo, null, 2));

  console.log('\n=== VIOLATIONS BY TOOL ===');
  console.log(JSON.stringify(results.byTool, null, 2));

  console.log('\n=== UNIQUE VIOLATIONS ===');
  console.log(JSON.stringify(results.uniqueViolations, null, 2));

  // Save final results
  fs.writeFileSync(OUTPUT_FILE, JSON.stringify(results, null, 2));
  console.log(`\nResults saved to: ${OUTPUT_FILE}`);
})();

2.2: Read Scan Results

After running the scan, read the results file:

cat /tmp/a11y-work/scan-results.json

The results include:

• pageInfo: Page structure, images, headings, media
• violations: All violations from all tools (deduplicated)
• byTool: Success/failure status per tool
• toolsSucceeded: Number of tools that completed (1-3)

2.3: Graceful Degradation Decision Tree

2.4: MANDATORY - Check for Videos and Trigger Pipeline

After reading scan results, check pageInfo.media.videoUrls:

// Check scan-results.json for videos
const results = JSON.parse(fs.readFileSync('/tmp/a11y-work/scan-results.json'));
if (results.pageInfo && results.pageInfo.media.videoUrls.length > 0) {
  console.log('=== VIDEOS DETECTED - TRIGGERING VIDEO PIPELINE ===');
  for (const video of results.pageInfo.media.videoUrls) {
    console.log(`Video: ${video.src}`);
    console.log(`  Has captions: ${video.hasCaptions}`);
  }
  // PROCEED TO STEP 7 IMMEDIATELY
}

IF videos detected AND hasCaptions=false → STEP 7 is MANDATORY before generating reports.

STEP 3: CONTEXT-AWARE REMEDIATION (LLM-POWERED)

THIS IS WHERE CLAUDE'S INTELLIGENCE MATTERS.

Generic tools output: aria-label="[DESCRIPTION]" You output: aria-label="Add to shopping cart" because you understand context.

3.1: Context Analysis (Use Your Reasoning)

For EACH violation, Claude must:

1. READ THE HTML CONTEXT - Don't just see <button class="btn">, see:

   <div class="product-card" data-product="Adidas Superstar">
     <img src="superstar.jpg" alt="White sneakers">
     <span class="price">$99</span>
     <button class="btn add-to-cart">  <!-- THIS IS THE VIOLATION -->
       <svg class="icon-cart">...</svg>
     </button>
   </div>
   

2. INFER PURPOSE from:

   • Class names: add-to-cart, wishlist, menu-toggle
   • Parent context: Inside .product-card with product data
   • Icon classes: icon-cart, icon-heart, icon-search
   • Nearby text: Product name, price, "Add to bag"
   • Page section: Header nav vs product grid vs checkout

3. GENERATE SPECIFIC FIX:

   <!-- NOT THIS (generic template) -->
   <button aria-label="[DESCRIPTION]">
   
   <!-- THIS (context-aware) -->
   <button aria-label="Add Adidas Superstar to cart - $99">
   

3.2: Confidence Scoring

Rate your confidence in each fix:

• 0.9+: Clear context (class="add-to-cart" near product name)
• 0.7-0.9: Reasonable inference (icon-cart class alone)
• <0.7: Needs human review (ambiguous context)

Include confidence in remediation.md:

### Button: `.product-card .btn` (Confidence: 0.95)
**Context:** Inside product card for "Adidas Superstar", has cart icon
**Fix:** `aria-label="Add Adidas Superstar to cart"`

3.2: Remediation Templates by Violation Type

Form Labels (WCAG 1.3.1, 3.3.2, 4.1.2)

<!-- Context: Input inside payment form, near "Card Number" text -->
<!-- Confidence: 0.95 -->

<!-- BEFORE -->
<input type="text" name="cardNumber" placeholder="1234 5678 9012 3456">

<!-- AFTER -->
<label for="card-number">Credit Card Number</label>
<input type="text"
       id="card-number"
       name="cardNumber"
       placeholder="1234 5678 9012 3456"
       aria-describedby="card-hint"
       autocomplete="cc-number"
       inputmode="numeric"
       pattern="[0-9\s]{13,19}">
<span id="card-hint" class="visually-hidden">Enter 16-digit card number</span>

<!-- RATIONALE -->
- Visible label aids all users
- aria-describedby provides additional context
- autocomplete enables autofill
- inputmode shows numeric keyboard on mobile
- pattern enables browser validation

Icon Buttons (WCAG 4.1.2)

<!-- Context: Button with SVG inside nav, classes include "menu-toggle" -->
<!-- Confidence: 0.92 -->

<!-- BEFORE -->
<button class="menu-toggle">
  <svg>...</svg>
</button>

<!-- AFTER -->
<button class="menu-toggle"
        type="button"
        aria-expanded="false"
        aria-controls="main-menu"
        aria-label="Open navigation menu">
  <svg aria-hidden="true" focusable="false">...</svg>
</button>

<!-- RATIONALE -->
- aria-label describes action, not icon
- aria-expanded communicates state
- aria-controls links to menu element
- SVG hidden from assistive tech (decorative)

Color Contrast (WCAG 1.4.3)

<!-- Context: Gray text (#767676) on white background -->
<!-- Current ratio: 4.48:1 (FAILS AA for normal text) -->
<!-- Required: 4.5:1 (AA) or 7:1 (AAA) -->

<!-- BEFORE -->
.low-contrast { color: #767676; background: #ffffff; }

<!-- AFTER (Option 1: Darken text - minimal change) -->
.accessible { color: #757575; background: #ffffff; } /* 4.6:1 - PASSES AA */

<!-- AFTER (Option 2: Higher contrast for AAA) -->
.high-contrast { color: #595959; background: #ffffff; } /* 7.0:1 - PASSES AAA */

<!-- COLOR ALTERNATIVES -->
| Original | AA Pass | AAA Pass | Notes |
|----------|---------|----------|-------|
| #767676  | #757575 | #595959  | Gray text |
| #0066cc  | #0055b3 | #003d82  | Link blue |
| #cc0000  | #b30000 | #8b0000  | Error red |

Heading Hierarchy (WCAG 1.3.1)

<!-- Context: Page has 10 H1 elements, skipped H2 levels -->

<!-- BEFORE (broken) -->
<h1>Welcome</h1>
<h1>Products</h1>      <!-- ERROR: Multiple H1s -->
<h4>Shoes</h4>         <!-- ERROR: Skipped H2, H3 -->
<h1>Contact</h1>

<!-- AFTER (correct) -->
<h1>Site Name - Main Page Title</h1>
<main>
  <section aria-labelledby="products-heading">
    <h2 id="products-heading">Products</h2>
    <h3>Shoes</h3>
    <h3>Clothing</h3>
  </section>
  <section aria-labelledby="contact-heading">
    <h2 id="contact-heading">Contact</h2>
  </section>
</main>

<!-- HEADING STRUCTURE VISUALIZATION -->
h1: Site Name - Main Page Title
├── h2: Products
│   ├── h3: Shoes
│   └── h3: Clothing
└── h2: Contact

Skip Links (WCAG 2.4.1)

<!-- Add as FIRST element inside <body> -->
<body>
  <a href="#main-content" class="skip-link">Skip to main content</a>
  <a href="#main-nav" class="skip-link">Skip to navigation</a>

  <header>
    <nav id="main-nav" aria-label="Main navigation">...</nav>
  </header>

  <main id="main-content" tabindex="-1">
    <!-- Main content -->
  </main>
</body>

<style>
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  background: #000;
  color: #fff;
  padding: 12px 24px;
  z-index: 10000;
  text-decoration: none;
  font-weight: bold;
  border-radius: 0 0 4px 4px;
  transition: top 0.2s;
}
.skip-link:focus {
  top: 0;
  outline: 3px solid #ffcc00;
  outline-offset: 2px;
}
</style>

Focus Indicators (WCAG 2.4.7)

/* NEVER do this */
*:focus { outline: none; } /* WCAG FAIL */

/* DO THIS - Custom focus styles */
:focus-visible {
  outline: 3px solid #005fcc;
  outline-offset: 2px;
}

/* Remove outline only for mouse users */
:focus:not(:focus-visible) {
  outline: none;
}

/* High contrast for interactive elements */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[role="button"]:focus-visible {
  outline: 3px solid #005fcc;
  outline-offset: 2px;
  box-shadow: 0 0 0 6px rgba(0, 95, 204, 0.2);
}

/* Dark backgrounds need light focus */
.dark-bg :focus-visible {
  outline-color: #ffffff;
  box-shadow: 0 0 0 6px rgba(255, 255, 255, 0.3);
}

Keyboard Navigation (WCAG 2.1.1, 2.1.2)

<!-- Custom interactive element needs keyboard support -->

<!-- BEFORE (inaccessible) -->
<div class="dropdown"
  Menu
</div>

<!-- AFTER (accessible) -->
<button type="button"
        class="dropdown-trigger"
        aria-expanded="false"
        aria-controls="dropdown-menu"
       
       
  Menu
</button>
<ul id="dropdown-menu" role="menu" hidden>
  <li role="none"><a role="menuitem" href="/page1">Page 1</a></li>
  <li role="none"><a role="menuitem" href="/page2">Page 2</a></li>
</ul>

<script>
function handleKeydown(event) {
  switch(event.key) {
    case 'Enter':
    case ' ':
      event.preventDefault();
      toggleMenu();
      break;
    case 'Escape':
      closeMenu();
      break;
    case 'ArrowDown':
      event.preventDefault();
      focusFirstMenuItem();
      break;
  }
}
</script>

Modal Focus Trap (WCAG 2.4.3)

// Focus trap for modals - REQUIRED for WCAG compliance
function trapFocus(modal) {
  const focusable = modal.querySelectorAll(
    'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
  );
  const first = focusable[0];
  const last = focusable[focusable.length - 1];

  // Focus first element when modal opens
  first?.focus();

  modal.addEventListener('keydown', (e) => {
    if (e.key === 'Tab') {
      if (e.shiftKey && document.activeElement === first) {
        e.preventDefault();
        last.focus();
      } else if (!e.shiftKey && document.activeElement === last) {
        e.preventDefault();
        first.focus();
      }
    }
    if (e.key === 'Escape') {
      closeModal();
    }
  });
}

// Return focus when modal closes
function closeModal() {
  modal.hidden = true;
  triggerButton.focus(); // Return focus to trigger
}

iframe Titles (WCAG 4.1.2)

<!-- All iframes MUST have descriptive titles -->
<iframe src="map.html" title="Store location map showing 5 nearby stores"></iframe>
<iframe src="video.html" title="Product demonstration video with captions"></iframe>
<iframe src="chat.html" title="Customer support chat window"></iframe>

STEP 4: USER IMPACT ANALYSIS

For each violation, calculate user impact:

4.1: Affected User Groups

4.2: Impact Severity Classification

BLOCKS-USAGE: User cannot complete task at all
  - Missing form labels on required fields
  - Keyboard traps
  - Critical buttons without accessible names

IMPAIRS-USAGE: User can complete task with difficulty
  - Low contrast (can read with effort)
  - Missing skip links (tedious navigation)
  - Incorrect heading structure (confusing)

MINOR-INCONVENIENCE: Suboptimal but functional
  - Empty alt on decorative images
  - Redundant ARIA
  - Non-semantic HTML that works

STEP 5: ROI-BASED PRIORITIZATION

Calculate priority for each remediation:

5.1: Priority Formula

PRIORITY_SCORE = (IMPACT_WEIGHT × USERS_AFFECTED) / EFFORT_HOURS

Where:
- IMPACT_WEIGHT: Critical=10, Serious=7, Moderate=4, Minor=1
- USERS_AFFECTED: Estimated % of users impacted
- EFFORT_HOURS: Estimated fix time (0.25 to 8 hours)

5.2: Effort Estimation Guide

5.3: Priority Output Format

| Rank | Violation | Impact | Users | Effort | ROI Score |
|------|-----------|--------|-------|--------|-----------|
| 1 | Form labels missing | Critical | 15% | 0.5h | 300 |
| 2 | Keyboard trap | Critical | 12% | 4h | 30 |
| 3 | Low contrast | Serious | 10% | 0.5h | 140 |
| 4 | Missing alt text | Serious | 8% | 0.25h | 224 |

STEP 6: PRODUCTION READINESS ASSESSMENT

6.1: Compliance Scoring

COMPLIANCE_SCORE = (PASSED_CRITERIA / TOTAL_CRITERIA) × 100

Production Ready if:
✓ Score ≥ 85%
✓ Zero critical violations
✓ Fewer than 3 serious violations
✓ All user journeys keyboard accessible

6.2: POUR Analysis (Perceivable, Operable, Understandable, Robust)

| Principle | Guidelines | Pass | Fail | Score |
|-----------|-----------|------|------|-------|
| Perceivable | 1.1-1.4 | 12 | 3 | 80% |
| Operable | 2.1-2.5 | 18 | 2 | 90% |
| Understandable | 3.1-3.3 | 8 | 1 | 89% |
| Robust | 4.1 | 4 | 1 | 80% |
| **TOTAL** | | **42** | **7** | **86%** |

STEP 7: VIDEO ACCESSIBILITY PIPELINE

Execute for EACH video detected on page.

7.1: Detect and Extract Video URLs (MANDATORY)

This step MUST be integrated into STEP 2 multi-tool scan.

Add this to the page.evaluate() in the multi-tool scan:

// In pageInfo extraction (STEP 2), add:
videos: {
  elements: [...document.querySelectorAll('video')].map(v => ({
    src: v.src || v.querySelector('source')?.src,
    fullUrl: new URL(v.src || v.querySelector('source')?.src || '', window.location.href).href,
    poster: v.poster,
    hasCaptions: v.querySelector('track[kind="captions"]') !== null,
    hasDescriptions: v.querySelector('track[kind="descriptions"]') !== null,
    duration: v.duration || 'unknown',
    autoplay: v.autoplay,
    muted: v.muted
  })),
  iframes: [...document.querySelectorAll('iframe')].map(iframe => {
    const src = iframe.src;
    const isVideo = /youtube|vimeo|dailymotion|wistia/.test(src);
    return isVideo ? { src, platform: src.match(/(youtube|vimeo|dailymotion|wistia)/)?.[1] } : null;
  }).filter(Boolean)
}

MANDATORY OUTPUT: Log all video URLs found:

=== VIDEOS DETECTED ===
Video 1: https://example.com/promo.mp4 (no captions, no descriptions)
YouTube iframe: https://youtube.com/embed/xxx

7.2: Download and Extract Frames (MANDATORY for each video)

For EACH video URL found in 7.1:

# Create output directory
mkdir -p /tmp/a11y-work/frames

# Download video (with retry and user-agent)
curl -L -A "Mozilla/5.0" --retry 3 -o /tmp/a11y-work/video.mp4 "FULL_VIDEO_URL"

# Verify download succeeded
if [ -f /tmp/a11y-work/video.mp4 ] && [ -s /tmp/a11y-work/video.mp4 ]; then
  echo "Video downloaded successfully"
  ffmpeg -i /tmp/a11y-work/video.mp4 -vf "fps=1/3" -frames:v 10 /tmp/a11y-work/frames/frame_%02d.jpg 2>/dev/null
  echo "Extracted $(ls /tmp/a11y-work/frames/*.jpg 2>/dev/null | wc -l) frames"
else
  echo "VIDEO DOWNLOAD FAILED - Document this in audit-summary.md"
fi

IF VIDEO DOWNLOAD FAILS:

1. Document the failure reason in audit-summary.md
2. Still create video-captions violation in violations.json
3. Add remediation instructions WITHOUT generated captions
4. Mark video pipeline as "blocked" not "skipped"

7.3: Analyze Each Frame with Claude Vision (MANDATORY)

USE THE READ TOOL ON EACH FRAME IMAGE.

Claude Code has native vision capabilities. When you Read an image file, you SEE it.

Read /tmp/a11y-work/frames/frame_01.jpg
Read /tmp/a11y-work/frames/frame_02.jpg
Read /tmp/a11y-work/frames/frame_03.jpg
... (continue for all frames)

For EACH frame, describe:

• SCENE: Setting, environment, lighting, location
• PEOPLE: Who appears, what they're doing, expressions, clothing
• PRODUCTS: Items shown (for e-commerce: product names, colors, styles)
• TEXT: Any visible text, logos, signs, prices
• ACTION: Movement, transitions, what's happening

Example output after reading frame_01.jpg:

Frame 1 (0:00-0:03): A woman in white Adidas sneakers running on a forest trail.
Morning light filters through trees. She wears black athletic leggings and a
gray tank top. The Adidas three-stripe logo is visible on her shoes.

THIS IS THE LLM VALUE. Generic tools output "[DESCRIBE CONTENT]". You output actual descriptions because you can SEE the image.

FALLBACK: If Read tool fails on images

Try Anthropic API directly:

const Anthropic = require('@anthropic-ai/sdk');
const fs = require('fs');
const client = new Anthropic();

const imageData = fs.readFileSync('/tmp/a11y-work/frames/frame_01.jpg').toString('base64');
const response = await client.messages.create({
  model: 'claude-sonnet-4-6',
  max_tokens: 500,
  messages: [{
    role: 'user',
    content: [
      { type: 'image', source: { type: 'base64', media_type: 'image/jpeg', data: imageData } },
      { type: 'text', text: 'Describe this video frame for accessibility captions.' }
    ]
  }]
});

LAST RESORT: Context-Based Inference (No Vision) If vision completely unavailable, infer from:

• Video filename: "product-demo.mp4" → product demonstration
• Page context: product page → product showcase
• Surrounding text: nearby headings and descriptions

Document for each frame:

• SCENE: Setting, environment, lighting
• PEOPLE: Who, actions, expressions, clothing
• OBJECTS: Products, props, equipment
• TEXT: Visible text, logos, signs
• ACTION: Movement, transitions
• COLORS: Dominant colors, accessibility-relevant

7.4: Generate WebVTT Captions

WEBVTT
Kind: captions
Language: {detected-language}

00:00:00.000 --> 00:00:03.000
[Description from frame_01 analysis]

00:00:03.000 --> 00:00:06.000
[Description from frame_02 analysis]

7.5: Generate Audio Descriptions

WEBVTT
Kind: descriptions
Language: en

00:00:00.000 --> 00:00:03.000
SCENE: [Detailed scene for blind users]
VISUAL: [What's on screen]
TEXT: [Any readable text]
ACTION: [What's happening]

STEP 8: GENERATE COMPREHENSIVE REPORTS

8.1: Required Output Files

Save ALL files to docs/accessibility-scans/{page-slug}/:

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