Airlock RLS MCP — Supabase leak checks inside your AI coding agent

Let Cursor, Claude Code, or any MCP client check a Supabase app for leaks while it builds it. It catches the most common vibe-coding footgun: a service_role key shipped to the browser, and Row Level Security that's off or wide open.

The engine is Airlock RLS (npm i airlock-rls), the CI gate for Supabase RLS. This package is a thin MCP wrapper around it.

Two tools

scan_site_for_exposed_key — give it a deployed URL. It reads the page and its JS bundles for an exposed Supabase service_role key (a service_role JWT or an sb_secret_... key). No database, no credentials, just the public URL. A hit means anyone who reads it bypasses every RLS policy. It never prints the full key.

audit_supabase_rls — give it a Postgres connection string. It fails on RLS-off tables, permissive (always-true) policies, and anon/authenticated tenant leaks. It reads only catalog metadata (pg_tables, pg_policies, grants), never your row data, so a read-only role is enough.

Add it to your MCP client

{
  "mcpServers": {
    "airlock": {
      "command": "npx",
      "args": ["-y", "airlock-rls-mcp"]
    }
  }
}

That's the same block for Cursor (~/.cursor/mcp.json), Claude Desktop (claude_desktop_config.json) and other MCP clients. With Claude Code:

claude mcp add airlock -- npx -y airlock-rls-mcp

Then ask the agent things like "scan https://myapp.com for an exposed Supabase key" or "audit the RLS on this database" and it calls the tools.

Requirements

Node.js 18 or newer.

Develop

npm install
npm run smoke   # starts the server and checks both tools are advertised

More

Guides on Supabase RLS, a live cross-tenant demo, and the hosted Airlock Monitor (continuous checks of your live database): shipsealed.com

License

MIT © Mateus Zingano