Gmail MCP Server

gmail-mcp

MCP server for Gmail - read, send, archive, and manage emails.

Use Cases

Flight check-in: "Check me in for my flight tomorrow" → finds your confirmation email, extracts the booking reference, and completes check-in with browser use.

Expense submission: "Submit my Amazon purchases from last week as expenses" → finds receipts, extracts amounts/categories, and files them in your expense system.

Package tracking: "Where's my package from Acme?" → finds the shipping notification, extracts the tracking number, and fetches current delivery status.

Find that attachment: "What did we settle on for the budget? Michelle sent me something yesterday" → locates the email and opens the attached spreadsheet.

Vacation mode: "I'm on holiday Dec 20-Jan 2" → sets up Gmail auto-reply, blocks your calendar, and updates your Slack status in one go.

Meeting follow-up: After a call, your assistant reads the Gemini transcript, summarizes key decisions, and drafts a follow-up email with action items.

(These are just examples - any workflow that needs email search, reading, or sending can use this.)

Setup

1. Create Google OAuth credentials

1. Go to Google Cloud Console
2. Create a new project (or use existing)
3. Enable the Gmail API
4. Go to APIs & Services → OAuth consent screen, set up consent screen
5. Go to APIs & Services → Credentials → Create Credentials → OAuth client ID
6. Choose Web application
7. Add http://localhost:3000/callback to Authorized redirect URIs
8. Note your Client ID and Client Secret

2. Run the server

GOOGLE_CLIENT_ID='your-client-id' \
GOOGLE_CLIENT_SECRET='your-client-secret' \
MCP_TRANSPORT=http \
npm start

The server runs on http://localhost:3000 by default. Change with PORT=3001.

3. Add to your MCP client

claude mcp add --transport http gmail-mcp http://localhost:3000/mcp

Architecture

This server acts as an OAuth proxy to Google:

graph LR
    A[MCP client] <--> B[gmail-mcp] <--> C[Google OAuth/API]

1. Server advertises itself as an OAuth authorization server via /.well-known/oauth-authorization-server
2. /register returns the Google OAuth client credentials
3. /authorize redirects to Google, encoding the client's callback URL in state
4. /callback receives the code from Google and forwards to the client's callback
5. /token proxies token requests to Google, injecting client credentials
6. /mcp handles MCP requests, using the bearer token to call Gmail API

The server holds no tokens or state - it just proxies OAuth to Google.

Tools

Gmail API Scopes

• gmail.readonly - Read messages and labels
• gmail.send - Send messages
• gmail.modify - Modify messages (archive, labels, trash)

Contributing

Pull requests are welcomed on GitHub! To get started:

1. Install Git and Node.js
2. Clone the repository
3. Install dependencies with npm install
4. Run npm run test to run tests
5. Build with npm run build

Releases

Versions follow the semantic versioning spec.

To release:

1. Use npm version <major | minor | patch> to bump the version
2. Run git push --follow-tags to push with tags
3. Wait for GitHub Actions to publish to the NPM registry.