@sitelint/auditor-mcp

v1.0.9

Published

8 hours ago

MCP server for SiteLint Auditor - WCAG and SiteLint accessibility, SEO, performance, and security audits via LLM

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accessibility a11y ada audit mcp modelcontextprotocol seo sitelint wcag performance security

SiteLint Auditor MCP Server

MCP server that runs SiteLint Auditor - WCAG and SiteLint Best Practices for accessibility, SEO, performance, and security audits via LLM agents.

Quick start

npx @sitelint/auditor-mcp

Requires Chromium (installed automatically by Puppeteer).

Tools

`audit_url`

Audit a live URL.

{
  "url": "https://example.com",
  "standards": ["wcag"],
  "auditTypes": ["accessibility"],
  "wcagLevels": ["A", "AA"],
  "wcagVersions": ["2.2"],
  "wcagCriteria": []
}

`audit_html`

Audit raw HTML without fetching a URL. Defaults to waitUntil: "load" so image-based rules (e.g. oversized images, size calculations) see fully loaded assets. A timeout guards against hanging external resources — if the load event never fires, the audit aborts with a clear error instead of hanging. Pass waitUntil: "domcontentloaded" to skip slow assets entirely.

All filter parameters are required — pass empty arrays to skip a filter.

WCAG audit:

{
  "html": "<!DOCTYPE html><html>...</html>",
  "standards": ["wcag"],
  "auditTypes": ["accessibility"],
  "wcagLevels": ["A", "AA"],
  "wcagVersions": ["2.2"],
  "wcagCriteria": ["1.1.1", "1.4.3"]
}

SiteLint best practices (proprietary SEO, performance, security):

{
  "html": "<!DOCTYPE html><html lang=\"en\"><head><title>Test</title></head><body></body></html>",
  "standards": ["sitelint"],
  "auditTypes": ["seo", "performance", "security"],
  "wcagLevels": [],
  "wcagVersions": [],
  "wcagCriteria": []
}

Full audit (everything):

{
  "html": "<!DOCTYPE html><html>...</html>",
  "standards": ["wcag", "sitelint"],
  "auditTypes": ["accessibility", "performance", "security", "seo"],
  "wcagLevels": ["A", "AA", "AAA"],
  "wcagVersions": ["2.0", "2.1", "2.2"],
  "wcagCriteria": []
}

`check_wcag_criterion`

Check a single WCAG criterion against a URL.

{
  "url": "https://example.com",
  "criterion": "1.1.1"
}

Returns pass/fail with violation count.

Filter parameters

Filters are ANDed — a rule must match every provided filter to run. On audit_url filters are optional (omit or pass empty arrays to skip). On audit_html all filter parameters are required — pass empty arrays to skip.

| Parameter | Values | Example | | --- | --- | --- | | standards | wcag, sitelint | ["wcag"] | | auditTypes | accessibility, performance, security, seo | ["accessibility", "seo"] | | wcagLevels | A, AA, AAA, best_practices | ["A", "AA"] | | wcagVersions | 2.0, 2.1, 2.2 | ["2.2"] | | wcagCriteria | WCAG criterion numbers | ["1.1.1", "1.4.3"] |

Omit a parameter (or pass empty array) to skip that filter.

Resources

| URI | Description | | --- | --- | | auditor://standards | Supported WCAG criteria with levels | | auditor://report/{id} | Full JSON report from a previous audit |

Configuration

Environment variables

| Variable | Default | Description | | --- | --- | --- | | AUDITOR_BROWSER_PATH | Puppeteer default | Custom Chromium/Chrome path | | AUDITOR_CONCURRENCY | 3 | Max concurrent audit pages (hard cap) | | AUDITOR_TIMEOUT | 30000 | Navigation/render timeout (ms) | | AUDITOR_HEADLESS | true | Set false to see browser | | AUDITOR_TRANSPORT | stdio | stdio or sse | | AUDITOR_PORT | 3100 | Port for SSE transport |

SSE / HTTP transport

Run the server over Streamable HTTP instead of stdio:

AUDITOR_TRANSPORT=sse AUDITOR_PORT=3100 npm start

The server listens on 127.0.0.1:3100 and accepts MCP requests via POST /. Host and Origin headers are validated (localhost only). Graceful shutdown on SIGINT/SIGTERM closes the browser and the HTTP server.

Client config:

{
  "mcpServers": {
    "sitelint-auditor": {
      "url": "http://127.0.0.1:3100"
    }
  }
}

CLI flags

auditor-mcp --bundle ./custom-bundle.js --timeout 60000 --headless false

| Flag | Env equivalent | | --- | --- | | --browser <path> | AUDITOR_BROWSER_PATH | | --concurrency <n> | AUDITOR_CONCURRENCY | | --timeout <ms> | AUDITOR_TIMEOUT | | --headless <bool> | AUDITOR_HEADLESS | | --bundle <path> | — | | --transport <stdio \| sse> | AUDITOR_TRANSPORT | | --port <n> | AUDITOR_PORT |

Integration guides

opencode

Add to ~/.config/opencode/opencode.json:

{
  "mcp": {
    "sitelint-auditor": {
      "type": "local",
      "command": ["npx", "-y", "@sitelint/auditor-mcp"]
    }
  }
}

For a local build:

{
  "mcp": {
    "sitelint-auditor": {
      "type": "local",
      "command": ["node", "/path/to/auditor-mcp/dist/cli.js"]
    }
  }
}

With custom Chromium:

{
  "mcp": {
    "sitelint-auditor": {
      "type": "local",
      "command": ["npx", "-y", "@sitelint/auditor-mcp"],
      "environment": {
        "AUDITOR_BROWSER_PATH": "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
        "AUDITOR_TIMEOUT": "60000"
      }
    }
  }
}

Claude Desktop

Edit claude_desktop_config.json:

{
  "mcpServers": {
    "sitelint-auditor": {
      "command": "npx",
      "args": ["-y", "@sitelint/auditor-mcp"]
    }
  }
}

VS Code (Cline)

In Cline extension settings → MCP Servers:

{
  "sitelint-auditor": {
    "command": "npx",
    "args": ["-y", "@sitelint/auditor-mcp"]
  }
}

VS Code (Continue)

In ~/.continue/config.json:

{
  "experimental": {
    "mcpServers": {
      "sitelint-auditor": {
        "command": "npx",
        "args": ["-y", "@sitelint/auditor-mcp"]
      }
    }
  }
}

AnythingLLM

{
  "mcpServers": {
    "sitelint-auditor": {
      "command": "npx",
      "args": ["-y", "@sitelint/auditor-mcp"]
    }
  }
}

Other MCP clients

Any MCP client can connect. Use stdio transport (default) for local tools, or AUDITOR_TRANSPORT=sse with AUDITOR_PORT=3100 for remote.

Build from source

git clone <repo>
cd auditor-mcp
npm install
npm run build

# Bundle the auditor engine
cp /path/to/auditor/dist/auditor.bundle.js vendor/
cp /path/to/auditor/app/translations/en-us.json vendor/translations/

Requirements

Node.js 20+
Chromium (auto-downloaded by Puppeteer, or point to existing via AUDITOR_BROWSER_PATH)
SiteLint Auditor bundle (vendored as vendor/auditor.bundle.js)

How it works

Launches headless Chromium via Puppeteer (single browser, pages capped by AUDITOR_CONCURRENCY)
Loads the target page and waits for it to settle (bounded by AUDITOR_TIMEOUT)
Injects the SiteLint Auditor JS bundle into the page
Runs a single-shot audit against the current DOM state
Formats results into a concise text report with grouping and truncation for long outputs
Stores full JSON as a resource accessible via auditor://report/{id}

Navigation failures, timeouts, and browser-launch errors are returned as readable messages rather than raw exceptions.

Limitations vs. embedded auditor

When SiteLint Auditor is embedded directly into a website via <script>, it watches for DOM mutations, re-tests dynamically loaded content, and provides an interactive sidebar UI. The MCP server does not do any of that — it takes a one-time snapshot of the page at the moment of injection. Content loaded after the audit starts (lazy images, infinite scroll, SPA route transitions) is not evaluated. For SPAs or pages with heavy dynamic content, consider waiting for full render before calling the tool.