Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@WCAG MCP Server explain success criterion 1.1.1 with examples"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
WCAG MCP Server for Agentic Systems - Powered by Official W3C Data with Full Understanding Documentation
A Model Context Protocol (MCP) server providing comprehensive access to WCAG 2.2 guidelines, techniques, glossary terms, and complete Understanding documentation for every success criterion. Works both locally (stdio) and remotely (Netlify Functions).
Add to your MCP client configuration:
{
"mcpServers": {
"wcag": {
"command": "npx",
"args": ["-y", "wcag-guidelines-mcp"]
}
}
}That's it! No cloning, no building - just add the config and start querying WCAG.
Related MCP server: aria-mcp
Complete WCAG 2.2 Coverage - All 87 success criteria with full details
Full Understanding Documentation - Intent, benefits, examples, and resources for every SC
Techniques Library - 400+ techniques (sufficient, advisory, failure patterns)
Glossary - 101 official WCAG term definitions
Version Tracking - See what's new in WCAG 2.2
This server now includes complete Understanding documentation parsed from the official W3C WCAG Understanding documents. For every success criterion, you get:
Brief Summary - Goal, what to do, and why it's important
Intent - Detailed explanation of the purpose and rationale
Benefits - Who benefits and how
Examples - Real-world examples of implementation
Resources - Curated list of tools and references
No more following external links - everything you need is right in the MCP response!
Complete WCAG 2.2 Coverage - All 87 success criteria with full details
Full Understanding Documentation - Intent, benefits, examples, and resources for every SC
Techniques Library - 400+ techniques (sufficient, advisory, failure patterns)
ACT Test Rules - 87+ standardized accessibility test rules
Glossary - 101 official WCAG term definitions
Version Tracking - See what's new in WCAG 2.2
This server now includes complete Understanding documentation parsed from the official W3C WCAG Understanding documents. For every success criterion, you get:
Brief Summary - Goal, what to do, and why it's important
Intent - Detailed explanation of the purpose and rationale
Benefits - Who benefits and how
Examples - Real-world examples of implementation
Resources - Curated list of tools and references
No more following external links - everything you need is right in the MCP response!
Tool | Description |
| Lists all four WCAG 2.2 principles (Perceivable, Operable, Understandable, Robust) |
| Lists WCAG 2.2 guidelines, optionally filtered by principle number (1-4) |
| Lists success criteria with optional filters by level (A/AA/AAA), guideline, or principle |
| Gets just the normative success criterion text and exceptions without Understanding docs |
| Gets comprehensive details including full Understanding documentation (intent, benefits, examples) |
| Gets full details for a specific guideline including all its success criteria |
| Searches success criteria by keyword in titles and descriptions |
| Gets all criteria for a conformance level, optionally including lower levels |
| Returns counts of success criteria grouped by level, principle, or guideline |
Tool | Description |
| Lists techniques, filter by technology (html, aria, css, pdf, general) or type |
| Gets details for a specific technique by ID (e.g., "H37", "ARIA1", "G94") |
| Gets all techniques (sufficient, advisory, failure) for a success criterion |
| Searches techniques by keyword |
| Gets failure patterns (common mistakes) for a success criterion |
Tool | Description |
| Gets the definition of a WCAG term (e.g., "programmatically determined") |
| Lists all 101 WCAG glossary terms |
| Searches the glossary by keyword |
Tool | Description |
| Lists all 9 success criteria added in WCAG 2.2 |
| Gets comprehensive context: SC + techniques |
| Returns server information and statistics |
This server uses official data from the W3C WCAG Repository:
WCAG JSON: Published WCAG 2.2 JSON
Understanding Docs: Parsed from official W3C Understanding HTML files in the submodule
4 Principles - Perceivable, Operable, Understandable, Robust
13 Guidelines - Organized under principles
87 Success Criteria - Levels A (32), AA (24), AAA (31)
400+ Techniques - HTML, ARIA, CSS, PDF, General, and more
101 Glossary Terms - Official WCAG definitions
# Clone with submodules
git clone --recurse-submodules https://github.com/joe-watkins/wcag-mcp.git
cd wcag-mcp
# Install dependencies and build data (automatically fetches WCAG data and Understanding docs)
npm installTo pull the latest WCAG data and Understanding documentation:
# Update submodule, fetch latest data from W3C, and parse Understanding docs
npm run buildThe build process:
Updates the W3C WCAG git submodule to the latest version
Fetches the latest WCAG 2.2 JSON data from W3C
Parses all Understanding documentation from HTML files
This runs automatically during npm install.
Add this to your Claude Desktop MCP settings:
{
"mcpServers": {
"wcag-mcp": {
"command": "node",
"args": ["<path to installed mcp>/wcag-mcp/src/index.js"]
}
}
}This project is configured to deploy as a Netlify Function.
Push this repository to GitHub
Connect it to Netlify via the Netlify dashboard
Netlify will automatically build and deploy
Once deployed, configure your Claude Desktop MCP settings to use the remote server:
{
"mcpServers": {
"wcag-mcp": {
"type": "stdio",
"command": "npx",
"args": ["mcp-remote@next", "https://your-site.netlify.app/mcp"]
}
}
}Replace your-site.netlify.app with your actual Netlify URL.
wcag-mcp/
├── data/
│ ├── wcag/ # W3C WCAG submodule (includes Understanding docs)
│ │ └── understanding/ # Understanding HTML files by WCAG version
│ │ ├── 20/ # WCAG 2.0 Understanding docs
│ │ ├── 21/ # WCAG 2.1 Understanding docs
│ │ └── 22/ # WCAG 2.2 Understanding docs
│ └── wcag.json # Enhanced WCAG data with Understanding content
├── scripts/
│ ├── fetch-wcag-data.js # Fetch WCAG JSON from W3C
│ └── parse-understanding-docs.js # Parse Understanding HTML files
├── src/
│ ├── index.js # MCP server with stdio transport
│ ├── tools.js # Tool definitions (20 tools)
│ └── data-helpers.js # Data access utilities
├── netlify/
│ └── functions/api.js # Netlify Function handler
└── package.jsonWCAG data from the W3C WCAG Repository (W3C Document License).
This software includes material copied from or derived from Web Content Accessibility Guidelines (WCAG) 2.2 https://www.w3.org/TR/WCAG22/. Copyright © 2023 W3C® (MIT, ERCIM, Keio, Beihang).
MIT
Returns counts of success criteria grouped by level, principle, or guideline.
Inputs: group_by (required).
Gets all success criteria for a specific conformance level. Optionally includes lower levels (e.g., AA includes A).
Inputs: level (required), include_lower.
Gets full details for a specific WCAG success criterion by its reference number (e.g., "1.1.1", "2.4.7", "4.1.2"), including complete Understanding documentation.
Inputs: ref_id (required).
Gets failure techniques (common mistakes) for a specific success criterion.
Inputs: ref_id (required).
Gets comprehensive context for a success criterion including techniques, test rules, and related glossary terms.
Inputs: ref_id (required).
Gets the definition of a WCAG glossary term.
Inputs: term (required).
Gets full details for a specific WCAG guideline including all its success criteria.
Inputs: ref_id (required).
Returns information about this WCAG MCP server and data source.
Inputs: no named parameters.
Gets the normative success criterion requirements - just the title and exception details without Understanding documentation.
Inputs: ref_id (required).
Gets details for a specific technique by ID (e.g., "H37", "ARIA1", "G94", "F65").
Inputs: id (required).
Gets all techniques (sufficient, advisory, and failures) for a specific success criterion.
Inputs: ref_id (required).
Lists all WCAG glossary terms.
Inputs: no named parameters.
Lists WCAG 2.2 guidelines, optionally filtered by principle number (1-4).
Inputs: principle.
Lists all four WCAG 2.2 principles: Perceivable, Operable, Understandable, and Robust.
Inputs: no named parameters.
Lists WCAG 2.2 success criteria with optional filters by level (A, AA, AAA), guideline (e.g., "1.1"), or principle (1-4).
Inputs: level, guideline, principle.
Lists WCAG techniques, optionally filtered by technology (html, aria, css, pdf, general, etc.) or type (sufficient, advisory, failure).
Inputs: technology, type.
Searches the WCAG glossary by keyword.
Inputs: query (required).
Searches techniques by keyword in titles.
Inputs: query (required).
Searches WCAG 2.2 success criteria by keyword in titles and descriptions.
Inputs: query (required), level.
Lists all success criteria that were added in WCAG 2.2.
Inputs: no named parameters.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
Loading tool schema changelog…
Scored across 20 tools
Most tools have distinct purposes targeting different WCAG entities (criteria, techniques, glossary terms, guidelines), but some overlap exists: get-criteria-by-level and list-success-criteria both retrieve criteria with filtering, and get-criterion/get-success-criteria-detail/get-full-criterion-context all provide criterion details with varying depth. Descriptions help differentiate these, but an agent might initially confuse them.
Tool names follow a highly consistent verb_noun pattern throughout, using kebab-case uniformly. Verbs like get, list, search, and count are applied predictably to nouns like criteria, techniques, glossary-terms, and guidelines, making the set easy to navigate and understand.
With 20 tools, the count is slightly high but reasonable for the comprehensive WCAG domain, covering principles, guidelines, criteria, techniques, and glossary terms. It feels thorough rather than bloated, though some consolidation (e.g., merging criterion detail tools) could streamline it without losing functionality.
The toolset provides complete coverage for exploring WCAG 2.2, including listing, retrieving details, and searching across all key components (principles, guidelines, success criteria, techniques, glossary). It supports filtering, contextual information, and even highlights updates in WCAG 2.2, leaving no obvious gaps for an agent working in this domain.
Scan URLs or HTML for WCAG 2.2 violations. 75-rule manifest, weighted score, shareable reports.
WCAG 2.2 rule reference for free; with an API key: what to fix on your sites and new checks.
Accessibility and WCAG data for your own websites: fix lists, live checks, and fix validation.
Accessibility compliance for AI coding tools. WCAG 2.2 reviews with shared evidence.
