Web Accessibility-Testing MCP Server

What is Web Accessibility-Testing MCP Server?

An MCP server that enables AI assistants like Claude to perform automated accessibility testing on web pages and HTML content using the Deque Axe-core library via Puppeteer.

How to use Web Accessibility-Testing MCP Server?

Install globally with npm install -g a11y-mcp-server and run a11y-mcp-server. Integrate with Claude Desktop by adding the server to the MCP settings file (claude_desktop_config.json on macOS, or the equivalent on Windows/Linux) using the npx -y a11y-mcp-server command.

Key features of Web Accessibility-Testing MCP Server

• Test any public URL for accessibility issues
• Test raw HTML strings for accessibility issues
• WCAG compliance testing against standards 2.0, 2.1, 2.2
• Color contrast analysis for WCAG compliance
• ARIA attribute validation
• Orientation lock detection

Use cases of Web Accessibility-Testing MCP Server

• Automatically audit a live website for accessibility violations during development
• Validate inline HTML snippets for WCAG compliance before deployment
• Check color combinations meet contrast ratio thresholds
• Verify proper ARIA attribute usage in custom components
• Detect content that forces a specific screen orientation

FAQ from Web Accessibility-Testing MCP Server

What does this server do that other accessibility testing tools don’t?

It integrates directly with AI assistants like Claude via the Model Context Protocol, allowing them to run Axe-core–based accessibility tests and interpret results conversationally.

Is this an official Deque Labs server?

No, this is an unofficial MCP server that uses the Deque Axe-core API. It is not affiliated with or maintained by Deque Labs.

What dependencies are required?

The server requires Node.js and npm. It installs the packages @modelcontextprotocol/sdk, puppeteer, and @axe-core/puppeteer, which includes a headless Chromium browser.

What types of content can be tested?

You can test any public URL or an HTML string. Supported WCAG tags include “wcag2aa” and other Axe-core standard tags. The server also provides dedicated tools for color contrast analysis, ARIA validation, and orientation lock detection.

How are results returned?

The server returns structured JSON containing violations with impact level, description, help URL, affected nodes, pass/incomplete/inapplicable counts, and test environment metadata.