WCAG MCP Server Suite

A modular suite of MCP (Model Context Protocol) servers for WCAG 2.1 accessibility validation.

Architecture

This monorepo contains individual focused servers plus an umbrella server for full WCAG coverage:

packages/
├── core/       # Shared types, criteria definitions, report formatting
├── text/       # Text accessibility (contrast, spacing, language)
├── keyboard/   # Keyboard navigation and focus (2.1.x, 2.4.x)
├── aria/       # ARIA roles, states, properties (4.1.x)
├── media/      # Captions, audio descriptions (1.2.x)
├── forms/      # Labels, error handling (1.3.x, 3.3.x)
├── structure/  # Headings, landmarks, reading order (1.3.x, 2.4.x)
└── full/       # Umbrella combining all servers

Quick Start

# Install dependencies
npm install

# Build all packages
npm run build

# Or build individually
npm run build:core
npm run build:text
npm run build:keyboard
# etc.

Packages

@wcag-mcp/core

Shared library with:

• TypeScript types for check results, reports, criteria
• Complete WCAG 2.1 criteria definitions (78 criteria) with categories
• Report formatting utilities (human-readable and machine-readable)

@wcag-mcp/text

Text accessibility validation.

WCAG Criteria: 1.4.3, 1.4.4, 1.4.5, 1.4.6, 1.4.8, 1.4.10, 1.4.12, 3.1.1, 3.1.2

Tools:

• check_contrast - Color contrast ratio (AA/AAA)
• check_text_spacing - Line-height, letter/word spacing
• check_line_length - Max 80 characters (AAA)
• check_language - Page lang attribute
• validate_text - Comprehensive text validation
• get_wcag_text_criteria - Reference data

@wcag-mcp/keyboard

Keyboard and pointer accessibility validation.

WCAG Criteria: 2.1.1, 2.1.2, 2.1.4, 2.2.1, 2.2.3, 2.4.3, 2.4.7, 2.5.1, 2.5.2, 2.5.4, 2.5.5, 3.2.1

Tools:

• check_keyboard_access - Keyboard operability, focus trapping
• check_focus_indicator - Focus visibility and contrast
• check_timing - Time limit adjustability
• check_motion - Motion actuation controls
• check_pointer_gestures - Complex gesture alternatives
• check_pointer_cancellation - Down-event cancellation
• check_target_size - Touch target dimensions
• get_wcag_keyboard_criteria - Reference data

@wcag-mcp/aria

ARIA and semantic accessibility validation.

WCAG Criteria: 2.5.3, 4.1.1, 4.1.2, 4.1.3

Tools:

• check_name_role_value - Accessible names, roles, states
• check_status_message - Live region announcements
• check_aria_attributes - ARIA attribute validity
• check_landmarks - Landmark region labeling
• check_label_in_name - Visible label in accessible name
• get_wcag_aria_criteria - Reference data

@wcag-mcp/media

Media accessibility validation.

WCAG Criteria: 1.2.1-1.2.9, 1.4.2, 2.2.2, 2.3.1, 2.3.2, 2.3.3

Tools:

• check_captions - Caption availability (prerecorded/live)
• check_audio_description - Audio description for video
• check_transcript - Text alternatives for media
• check_media_controls - Autoplay control mechanisms
• check_animation - Animation pause/stop controls
• check_flashing - Flash frequency thresholds
• check_sign_language - Sign language interpretation
• get_wcag_media_criteria - Reference data

@wcag-mcp/forms

Form accessibility validation.

WCAG Criteria: 1.3.5, 3.2.2, 3.3.1-3.3.6

Tools:

• check_form_labels - Label associations
• check_input_purpose - Autocomplete attributes
• check_error_identification - Error messaging
• check_error_prevention - Submission safeguards
• check_input_constraints - Format instructions
• check_on_input - Context change on input
• validate_form - Comprehensive form validation
• get_wcag_forms_criteria - Reference data

@wcag-mcp/structure

Page structure and navigation validation.

WCAG Criteria: 1.3.1, 1.3.2, 2.4.1, 2.4.2, 2.4.4, 2.4.5, 2.4.6, 2.4.9, 2.4.10, 3.2.3, 3.2.4

Tools:

• check_heading_structure - Heading hierarchy
• check_page_title - Title descriptiveness
• check_link_purpose - Link text clarity
• check_bypass_blocks - Skip links, landmarks
• check_reading_order - DOM/visual order match
• check_info_relationships - Semantic structure
• check_multiple_ways - Navigation methods
• check_consistent_navigation - Navigation consistency
• check_consistent_identification - Component labeling
• get_wcag_structure_criteria - Reference data

@wcag-mcp/full

Umbrella server with overview and export tools.

Tools:

• get_all_wcag_criteria - All criteria filtered by level/category
• get_wcag_checklist - Conformance level checklist
• wcag_help - Usage help
• export_report - Export any check's results to a Markdown file

Exporting Results

Any WCAG check tool returns a MACHINE-READABLE JSON block in its output. Pass that JSON to export_report to save a formatted Markdown report:

WCAG_Results_2026-02-24.md

The report includes:

• Summary table (total/passed/failed/warnings)
• Breakdown by conformance level (A/AA/AAA)
• Detailed failures with recommendations and WCAG reference links
• Warnings and passed checks

Optional parameters:

• outputDir — directory to save the file (defaults to current working directory)
• title — custom report title
• url — URL of the page audited
• notes — additional notes appended to the report

Usage with Claude Code

Add to your .mcp.json:

{
  "mcpServers": {
    "wcag-text": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/text/dist/index.js"]
    },
    "wcag-keyboard": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/keyboard/dist/index.js"]
    },
    "wcag-aria": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/aria/dist/index.js"]
    },
    "wcag-media": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/media/dist/index.js"]
    },
    "wcag-forms": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/forms/dist/index.js"]
    },
    "wcag-structure": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/structure/dist/index.js"]
    }
  }
}

Or use the umbrella server:

{
  "mcpServers": {
    "wcag": {
      "command": "node",
      "args": ["/path/to/wcag-mcp/packages/full/dist/index.js"]
    }
  }
}

Auto-Approve Tools

By default, Claude Code prompts for permission on every MCP tool call. To auto-approve all WCAG tools, add this to your Claude Code settings.

Per-project (.claude/settings.local.json):

{
  "permissions": {
    "allow": [
      "mcp__wcag*"
    ]
  }
}

Global (~/.claude/settings.json):

{
  "permissions": {
    "allow": [
      "mcp__wcag*"
    ]
  }
}

The wildcard mcp__wcag* matches all tools from every WCAG MCP server (wcag-text, wcag-keyboard, wcag-aria, etc.).

Development

# Watch mode for development
cd packages/text && npm run dev

# Build all
npm run build

# Clean all dist folders
npm run clean

Adding New Checks

Import shared utilities from @wcag-mcp/core:

import {
  createReport,
  formatToolResponse,
  getCriteriaByCategory,
  type CheckResult
} from "@wcag-mcp/core";

// Get criteria for a category
const criteria = getCriteriaByCategory("keyboard");

// Create a check result
const result: CheckResult = {
  criterion: "2.1.1",
  name: "Keyboard",
  level: "A",
  status: "pass",
  message: "All functionality is keyboard accessible"
};

// Create formatted report
const report = createReport([result], {
  title: "My Check",
  category: "keyboard"
});

License

MIT