wcagc-mcp
An MCP server that lets an AI assistant (Claude, ChatGPT, or
any MCP-compatible client) run real, deterministic accessibility scans through
wcagc — axe-core under the hood, not an LLM guess. Every scan result carries
an explicit coverage disclaimer and never claims "compliant": automated testing finds only a
portion of accessibility barriers, and this tool says so in every response.
This package is a thin, stateless adapter. It holds no database, no scan logic, and no
secrets beyond the wcagc API base URL — it translates MCP tool calls into HTTP calls against the
wcagc API and forwards the caller's own bearer. All authentication, entitlements, quotas, and
scan orchestration live in the API; this code is safe to read end to end.
Two ways to run it
Local (stdio) — for Claude Desktop, Cursor, or any MCP client that spawns a local process:
Configure your MCP client with:
{
"mcpServers": {
"wcagc": {
"command": "npx",
"args": ["-y", "@wcagc/mcp"],
"env": {
"WCAGC_MCP_KEY": "<your mcp:scan API key>"
}
}
}
}
Mint an mcp:scan key from your wcagc account under Settings → API keys — available on every
plan, with a daily quota on Free/Starter and unlimited on Pro/Agency.
Hosted (Streamable HTTP + managed OAuth) — what Claude web/desktop/mobile connectors and
ChatGPT use, since neither runs a local process for you. Add this remote MCP connector:
https://mcp.wcagc.com/mcp
The client discovers /.well-known/oauth-protected-resource/mcp, opens the wcagc login/consent
flow, and binds the connection to one Organization. No key copy/paste is required. API-key bearer
authentication remains supported for local stdio and CI.
ChatGPT availability depends on the ChatGPT plan and on whether the client permits action tools;
scan_url creates a scan and is not a read-only operation. See
wcagc.com/integrations/mcp.
| Tool | Plan | What it does |
|---|
scan_url | all | Scan any public URL, or a registered site for full tracking (Pro+). |
check_pdf | all | Run a PDF/UA-1 structure check on a public PDF. |
get_scan · get_findings | all | Read a scan's status, severity counts, and findings. |
list_sites | Pro+ | List the account's registered sites. |
scan_site | Pro+ | Crawl and scan every reachable page of a registered site. |
get_run · get_run_findings | Pro+ | Read a full-site run. |
run_journey | Pro+ | Replay a saved multi-step journey and check each step. |
get_trends | Pro+ | Read a site's violation-count history over time. |
Every scan-producing tool returns the coverage disclaimer in both the text content and the
structured content. There is no score, grade, or conformance verdict — automated testing finds
roughly 30–57% of accessibility issues, and the remainder needs manual review.
Configuration
| Env var | Used by | Meaning |
|---|
WCAGC_API_BASE_URL | both | The wcagc API to call. Defaults to https://api.wcagc.com; set it only when self-hosting. |
WCAGC_MCP_KEY | stdio | Your mcp:scan API key. |
PORT | hosted | Port to listen on (default 8080). |
WCAGC_MCP_ALLOWED_HOSTS | hosted | Comma-separated Host-header allowlist (DNS-rebinding protection when bound to 0.0.0.0). |
WCAGC_MCP_INTROSPECT_TTL_SECONDS | hosted | How long a verified bearer is cached before re-checking with the API (default 60). |
WCAGC_OAUTH_ISSUER | hosted | Expected OAuth issuer. |
WCAGC_OAUTH_JWKS_URL | hosted | Authorization Server public JWKS URL. |
WCAGC_MCP_SERVER_URL | hosted | Canonical RFC 9728 protected-resource URL. |
WCAGC_OAUTH_JWKS_TTL_SECONDS | hosted | JWKS cache TTL; an unknown kid triggers an immediate refetch. |
Development
npm install
npm run dev
npm run start:stdio
npm run typecheck
npm run verify
License
MIT — see LICENSE.