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AccessibilityHub is a Model Context Protocol (MCP) server that orchestrates professional-grade web accessibility testing tools. It enables AI assistants like Claude to analyze websites for WCAG compliance, check color contrast, and provide detailed remediation guidance with enriched human context.

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What is AccessibilityHub?

AccessibilityHub provides AI assistants with access to industry-standard accessibility testing tools:
  • axe-core - Comprehensive WCAG 2.0/2.1 compliance checking
  • Pa11y - Alternative WCAG testing engine for cross-validation
  • Lighthouse - Google’s accessibility scoring and audit system
  • Color Contrast Analysis - Dedicated WCAG 2.1 and APCA (WCAG 3.0 draft) contrast checking
Through the Model Context Protocol, these tools become available to any MCP-compatible client, allowing you to have natural conversations about accessibility issues and receive detailed, actionable guidance.

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Key Features

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Enriched Human Context

Every accessibility issue includes enriched context beyond raw tool output: 
{
  "ruleId": "image-alt",
  "severity": "serious",
  "wcag": {
    "criterion": "1.1.1",
    "level": "A",
    "principle": "perceivable"
  },
  "humanContext": "**Non-text content (WCAG 1.1.1 - Level A)**\n\nAll non-text content must have a text alternative...",
  "affectedUsers": ["screen-reader", "low-vision"],
  "priority": "critical",
  "remediationEffort": "low",
  "suggestedActions": [
    "Add descriptive alt attribute to images",
    "Use aria-label for decorative icons with function",
    "Mark decorative images with empty alt=\"\""
  ]
}
Each issue tells you:
  • What the problem is (WCAG criterion, description)
  • Who it affects (screen-reader users, keyboard-only, low-vision, etc.)
  • Why it matters (real-world impact with examples)
  • How to fix it (step-by-step remediation actions)
  • When to fix it (priority based on severity and user impact)
  • Effort required (low, medium, high)

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Multiple Analysis Tools

analyze-with-axe

Fast, accurate WCAG analysis using axe-core with low false positive rates

analyze-with-pa11y

Alternative testing engine for cross-validation and maximum coverage

analyze-with-lighthouse

Google’s accessibility scoring (0-100) with score improvement guidance

analyze-contrast

Dedicated color contrast analysis with suggested color fixes for WCAG compliance

analyze-mixed

Run multiple tools in parallel with intelligent deduplication

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Pre-Built Prompt Templates

Common workflows are available as MCP prompts:
  • full-accessibility-audit - Comprehensive audit using all three tools with Lighthouse scoring
  • quick-accessibility-check - Fast critical issue identification
  • pre-deploy-check - GO/NO-GO deployment decision based on blocking issues
  • quick-wins-report - High-impact, low-effort fixes for sprint planning
  • contrast-check - Detailed color contrast review with CSS fix suggestions
  • lighthouse-score-improvement - Phased plan to reach target accessibility scores
  • explain-wcag-criterion - Deep educational dive into any WCAG success criterion

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WCAG Reference Resources

AccessibilityHub exposes MCP resources for quick WCAG lookups:
  • wcag://criteria - Complete WCAG 2.1 criteria reference
  • wcag://criteria/{id} - Specific criterion details (e.g., wcag://criteria/1.4.3)
  • wcag://criteria/level/AA - Filter by conformance level
  • contrast://thresholds/wcag21 - WCAG 2.1 contrast requirements
  • contrast://thresholds/apca - APCA (WCAG 3.0 draft) thresholds
  • lighthouse://audits - Lighthouse accessibility audit catalog

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Why Use AccessibilityHub?

  • Catch accessibility issues during development, not after deployment
  • Get actionable fix suggestions with code examples
  • Prioritize issues by user impact and remediation effort
  • Integrate accessibility checks into your workflow naturally through AI assistants
  • Leverage multiple industry-standard tools in one place
  • Cross-validate findings between axe-core and Pa11y
  • Access detailed WCAG criteria explanations on demand
  • Generate compliance reports with human-readable context
  • Understand the real-world impact of accessibility issues
  • Plan sprints with quick-wins reports (high impact, low effort)
  • Make informed deployment decisions with pre-deploy checks
  • Track Lighthouse accessibility scores over time
  • Each issue includes educational context about WCAG criteria
  • Understand which users are affected and how
  • See real-world examples of accessibility barriers
  • Learn best practices through suggested remediation actions

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How It Works

1

Install AccessibilityHub

Install the MCP server using npm, pnpm, or run directly with npx (no installation needed).
2

Configure Your MCP Client

Add AccessibilityHub to your MCP client configuration (Claude Desktop, Cursor, Windsurf, etc.).
3

Ask Your AI Assistant

Simply ask: “Analyze the accessibility of https://example.com” and receive detailed results.
4

Review & Fix Issues

Get prioritized issues with human-readable context, affected users, and step-by-step remediation guidance.

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Example Interaction

You: Analyze the accessibility of https://example.com

Claude: I'll analyze that page using our accessibility tools...

[Runs analyze-mixed tool with axe-core and Pa11y]

I found 8 accessibility issues:

🔴 Critical (2 issues)
- Missing alt text on 2 images (WCAG 1.1.1)
  Affects: screen-reader, low-vision users
  Fix: Add descriptive alt attributes
  Effort: Low

🟠 Serious (3 issues)
- Insufficient color contrast on form labels (WCAG 1.4.3)
  Current ratio: 2.8:1, Required: 4.5:1
  Suggested color: #767676
  Affects: low-vision, color-blind users
  Effort: Low

- Form inputs missing associated labels (WCAG 1.3.1)
  Affects: screen-reader users
  Effort: Low

[...]

You: Show me how to fix the image alt text issue

Claude: Here's how to fix the missing alt text:

[Provides before/after code examples with explanations]

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Requirements

  • Node.js ≥ 20
  • Chrome/Chromium (automatically downloaded by Puppeteer on first run)
  • MCP-compatible client (Claude Desktop, Cursor, Windsurf, Claude Code CLI, etc.)

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Next Steps

Quick Start

Get up and running in 5 minutes

Installation

Detailed installation instructions for all package managers

MCP Server Concepts

Learn how AccessibilityHub implements MCP

Workflows Guide

Recommended workflows for common tasks

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