Firebase Security MCP server

MCP server exposing the firebase-security auditor as tools any MCP-compatible AI agent (Claude Code, Cursor, Cline, etc) can call.

Tools

• audit_rules — scan a firestore.rules file (and optionally probe a deployed project ID). Detects match /{document=**} { if true; }, bare if true, auth != null without ownership, expired test-mode timestamp rules, public storage reads, missing default-deny.
• list_findings — list cached findings, filterable by severity.
• preview_fix — show the rule snippet that closes a given finding (paste into your firestore.rules, then firebase deploy --only firestore:rules).

Install

npx -y @perufitlife/firebase-security-mcp

Claude Code config

Add to ~/.config/claude-desktop/config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "firebase-security": {
      "command": "npx",
      "args": ["-y", "@perufitlife/firebase-security-mcp"],
      "env": {
        "FIREBASE_RULES_PATH": "/path/to/firestore.rules",
        "FIREBASE_PROJECT_ID": "my-firebase-project"
      }
    }
  }
}

Both env vars are optional — you can pass rules_path / project_id per tool call.

Active probe

If you provide project_id, the auditor sends an unauthenticated GET to:

https://firestore.googleapis.com/v1/projects/{project-id}/databases/(default)/documents

If documents come back, the deployed DB is leaking and the finding is confirmed: true with document count + bytes returned + sample paths.

Source + license

MIT. CLI/skill repo: https://github.com/Perufitlife/firebase-security-skill

For the full BaaS family (MCP servers for Supabase, PocketBase, Appwrite, Hasura/Nhost), see https://github.com/Perufitlife.