# Accessibility Testing MCP
An MCP server for accessibility testing using **axe-core** and **IBM Equal Access**. Choose your testing engine or use both for comprehensive coverage.
## Example Prompts
- "Test the accessibility of https://example.com"
- "Test the accessibility of https://example.com" blockers only output issues in chat: What is the Issue, Who it Impacts, How to Fix, WCAG, Severity, Code Snippet"
### Dual Engine Support
- **Axe-core** (Deque) - Industry standard, zero false positives
- **IBM Equal Access** - Comprehensive IBM accessibility requirements
### Multi-Screen Testing
Test at multiple viewport sizes to catch responsive accessibility issues.
### Tools
| Tool | Description |
|------|-------------|
| `analyze_url` | Test any URL for accessibility issues |
| `analyze_url_json` | URL test with raw JSON output |
| `analyze_html` | Test HTML content directly |
| `analyze_html_json` | HTML test with raw JSON output |
| `get_rules` | List available accessibility rules |
All tools accept an optional `engine` parameter (`"axe"` or `"ace"`).
###
## Installation
```bash
npm install
npm run build
```
## Configuration
### Environment Variables
Configure via MCP config `env` section:
| Variable | Values | Default | Description |
|----------|--------|---------|-------------|
| `A11Y_ENGINE` | `axe`, `ace` | `axe` | Testing engine |
| `WCAG_LEVEL` | `2.0_A`, `2.0_AA`, `2.1_A`, `2.1_AA`, `2.2_AA`, etc. | `2.1_AA` | WCAG version & level |
| `BEST_PRACTICES` | `true`, `false` | `true` | Include best practices/recommendations |
| `SCREEN_SIZES` | Comma-separated `WIDTHxHEIGHT` | `1280x1024` | Viewport sizes to test |
| `HEADLESS_BROWSER` | `true`, `false` | `true` | Run browser in headless mode; set to `false` to open visible browser |
The `WCAG_LEVEL` setting automatically configures both Axe-core tags and IBM Equal Access policies.
### VS Code (GitHub Copilot)
Add to VS Code settings (JSON):
```jsonc
"mcp": {
"servers": {
"accessibility-testing-mcp": {
"type": "stdio",
"command": "node",
"args": ["/path/to/accessibility-testing-mcp/build/index.js"],
"env": {
"A11Y_ENGINE": "axe",
"WCAG_LEVEL": "2.2_AA",
"BEST_PRACTICES": "true",
"SCREEN_SIZES": "1280x1024,320x640",
"HEADLESS_BROWSER": "true"
}
}
}
}
```
### Claude Desktop
Add to `claude_desktop_config.json`:
```json
{
"mcpServers": {
"accessibility": {
"command": "node",
"args": ["/path/to/accessibility-testing-mcp/build/index.js"],
"env": {
"A11Y_ENGINE": "ace",
"WCAG_LEVEL": "2.2_AA",
"BEST_PRACTICES": "true"
}
}
}
}
```
## Understanding Results
### Axe-core Output
- **Violations**: Definite accessibility failures
- **Incomplete**: Needs manual review
- **Passes**: Rules that passed
- **Inapplicable**: Rules that don't apply
### IBM Equal Access Output
- **Violations**: Accessibility failures
- **Potential Violations**: Needs review
- **Recommendations**: Suggested improvements (when BEST_PRACTICES=true)
- **Manual Checks**: Requires human testing
## WCAG_LEVEL Values
| Level | Description |
|-------|-------------|
| `2.0_A` | WCAG 2.0 Level A |
| `2.0_AA` | WCAG 2.0 Level AA |
| `2.1_A` | WCAG 2.1 Level A |
| `2.1_AA` | WCAG 2.1 Level AA (default) |
| `2.1_AAA` | WCAG 2.1 Level AAA |
| `2.2_A` | WCAG 2.2 Level A |
| `2.2_AA` | WCAG 2.2 Level AA |
| `2.2_AAA` | WCAG 2.2 Level AAA |
## Dependencies
- **@modelcontextprotocol/sdk** - MCP server framework
- **axe-core** - Deque accessibility testing engine
- **accessibility-checker** - IBM Equal Access engine
- **playwright** - Headless browser automation
## License
MIT
