A11y MCP is an MCP (Model Context Protocol) server that gives LLMs access to web accessibility testing APIs. This server uses the Deque Axe-core API and Puppeteer to allow LLMs to analyze web content for WCAG compliance and identify accessibility issues.

The server provides several key features including testing web pages for accessibility issues, testing HTML snippets for accessibility issues, WCAG compliance testing against various standards (2.0, 2.1, 2.2), customizable tests with specific accessibility tags/standards, rule exploration for available accessibility rules, color contrast analysis for WCAG compliance, ARIA validation for proper attribute usage, and orientation lock detection for content that forces specific screen orientations.

The server works by providing specific tools that LLMs can call through the Model Context Protocol. These tools include test_accessibility for testing URLs, test_html_string for testing HTML content, get_rules for exploring available rules, check_color_contrast for color compliance testing, and check_orientation_lock for detecting orientation restrictions.

The server returns structured JSON results containing violations, passes, incomplete tests, and inapplicable tests with detailed information about each accessibility issue found, including impact levels, descriptions, help URLs, and failure summaries.

The product targets developers and organizations working with LLMs who need to integrate web accessibility testing capabilities into their AI applications. It integrates with Claude Desktop through MCP configuration and supports various WCAG standards.