MessagesBridge is a Model Context Protocol (MCP) connector that lets ChatGPT work with your iMessage conversations and Contacts. It never uploads your messages to a third party — every action runs on your own Mac through a tiny local agent. The cloud piece is only a stateless relay that shuttles requests between ChatGPT and your Mac.

  ChatGPT  ──OAuth──►  MessagesBridge relay  ──job queue──►  apple-messages-agent  ──►  Messages.app + Contacts
 (connector)          (Vercel, stateless)      (your Mac, polls & executes)        (on your Mac)

Your Mac is the only place your messages are ever read or contacts written. The relay stores only short-lived job payloads and your account record; it never sees a message unless a job is in flight, and jobs expire in seconds.

For users — 3 steps

1. Create your account at messagesbridge.vercel.app and generate a pairing code.

2. Install the Mac agent (needs Node 18+):

npx apple-messages-agent pair <YOUR-CODE>   # link this Mac to your account
npx apple-messages-agent install            # keep it running on every restart

The agent needs two macOS permissions, granted once: Full Disk Access so it can read your message history (System Settings → Privacy & Security → Full Disk Access), and Automation the first time it sends a message or reads Contacts — macOS asks "Terminal wants to control Messages" and to access Contacts; click OK.

3. Connect ChatGPT: Settings → Plugins → turn on Developer mode (Security & login) → Create a custom plugin → paste the MCP Server URL https://messagesbridge.vercel.app/mcp → Authentication OAuth → sign in & Allow.

That's it. In a new chat: "Search my messages for the dinner plans" or "Text Sarah that I'm running 10 minutes late." (You confirm every send before it goes out.)

Your Mac must be awake with the agent running. npx apple-messages-agent install makes it start automatically at login and restart if it ever crashes.

Managing the agent

npx apple-messages-agent status      # is it paired & reachable?
npx apple-messages-agent logs        # recent activity
npx apple-messages-agent uninstall   # stop auto-start

What ChatGPT can do

Reads come first; the only write tools are send_message and create_contact, and each is confirmed by you in ChatGPT before it runs. Sends always go to one recipient at a time — never in bulk.

Self-hosting

You can run your own relay so nothing depends on the hosted instance.

Prereqs: a Vercel account and a Supabase project (free tiers are fine).

1. Storage — in your Supabase project's SQL editor, run supabase/schema.sql. It creates a tiny Redis-shaped KV + queue surface (nb_* functions) with RLS on.
2. Deploy the server/ directory to Vercel.
3. Set env vars (see server/.env.example):
   • SUPABASE_URL, SUPABASE_SERVICE_ROLE_KEY — your project + service-role key
   • JWT_SECRET — openssl rand -hex 32
4. Verify: curl https://YOUR-APP.vercel.app/api/health → redisConfigured, redisOk, jwtSecretSet all true.
5. Point the agent at it: npx apple-messages-agent pair <CODE> --server https://YOUR-APP.vercel.app.

How it works

• Auth — OAuth 2.1 with PKCE and Dynamic Client Registration (RFC 7591). ChatGPT registers itself, the user signs in on the MessagesBridge consent page, and ChatGPT gets a scoped MCP access token. JWTs are HMAC-signed; three kinds (session, agent, mcp) with distinct privileges. Optional email verification via Resend (RESEND_API_KEY); off unless configured, and enforcement is opt-in (REQUIRE_EMAIL_VERIFICATION).
• Relay — MCP tool call → job pushed to jobs:<user> (TTL ≤ the caller's wait window, so an abandoned job can't run late) → the Mac agent (holding a hanging long-poll) is handed the job within ~200ms, executes it, pushes the result → the MCP handler returns it. The long-poll means jobs are delivered on arrival rather than on a fixed interval, so relay overhead is ~300ms instead of ~1s. The agent is considered "online" only while it's actively connected.
• Agent — a dependency-free Node CLI. Read tools query the Messages chat.db directly (read-only SQLite); send and contact tools run via JXA (osascript -l JavaScript) against Messages.app and Contacts; arguments are passed as JSON over argv (never shell-interpolated). A macOS LaunchAgent keeps it alive across logins and crashes.

Repository layout

server/    Vercel functions: OAuth + MCP endpoint + relay        (deploy this)
agent/     apple-messages-agent — the npm-published Mac CLI          (users npx this)
kit/       Browser automations: register the dev-mode connector AND
           fill the OpenAI directory submission (see kit/README.md)
supabase/  schema.sql for self-hosting the storage
test/      end-to-end OAuth + MCP integration test

Development

# server
cd server && cp .env.example .env.local   # fill in, then: vercel dev
# end-to-end test against a live deployment (reads ../.env.local)
node test/e2e-oauth.mjs
# agent unit tests
node --test agent/test-agent-unit.mjs

Security & privacy

• Messages are read and sent, and contacts read and added, only on your Mac. The relay never persists message content — job payloads live in Redis-shaped storage with a short TTL and are deleted on delivery.
• The agent token is stored at ~/.messagesbridge-agent.json (mode 600).
• No secrets are committed; see .gitignore and the .env.example files.
• Write tools are marked destructive so ChatGPT asks before it sends a message or adds a contact — every send goes to one confirmed recipient at a time, never in bulk.

License

MIT © Isaiah Dupree