Gmail MCP Server

A working example of connecting Claude to a real business tool — Gmail — the way it should be done: with proper login security, the AI only able to do what it's explicitly allowed to do, and no way for it to take an irreversible action (like sending an email) without a clear checkpoint.

The problem this solves

AI assistants like Claude are increasingly expected to do things, not just talk — search an inbox, draft a reply, flag something urgent — instead of a person copy-pasting between a chat window and their actual tools. That capability is genuinely useful, but connecting an AI assistant directly to something as sensitive as an email account raises an obvious question: what happens if it gets it wrong, or is tricked into doing something it shouldn't?

Most quick "connect my AI to my inbox" setups skip past that question — they hand over broad access and hope for the best. That's the gap this project is built to close. It's a demonstration, using a real Google account and the real Gmail API (not a mock or toy example), of what a properly scoped AI-to-business-tool integration looks like: the AI gets exactly the access it needs for the job, nothing more, and the riskiest action (sending real email) requires an explicit extra step rather than happening automatically.

Related MCP server: gmail-mcp-server

How it stays safe, in plain terms

• A specific, limited key — not the master key. Logging in grants three narrow permissions (read mail, draft/send mail, apply labels). There is no permission to delete anything, change account settings, or touch anything outside Gmail.

• The key is locked in a safe. Once you log in, the credentials that let Claude access your inbox are encrypted on your own computer. They're never sent anywhere else, and the encryption key lives only in a local file that's never shared or uploaded.

• Drafting and sending are two separate, deliberate steps. Claude can prepare a reply as a draft at any time — that's harmless and reversible, the same as you starting an email and not hitting send. Actually sending it is a separate action, clearly flagged to whatever app is running Claude as a sensitive one-way step, so it isn't something that happens as a side effect of Claude just being "helpful."

• Labels can't be used to hide or destroy mail. Claude can tag messages with custom labels you create (e.g. "Needs Reply"), but it's structurally blocked from touching Gmail's built-in Trash/Spam/Archive controls through that same feature — a subtle way "just add a label" could otherwise be misused.

The full technical breakdown — exact permissions requested, what's reversible vs. not, and what the honest residual risk is — is in SECURITY.md.

Why build this instead of using Google's own Gmail MCP integration

Google has since released its own first-party remote MCP server for Gmail. For someone who just wants Gmail-in-Claude working today, that's the faster path. This project exists for a different reason: to show, on a tool everyone recognizes, the underlying skill of building this kind of integration from scratch — the login flow, the credential storage, the tool design, the safety boundaries — for the many business tools (CRMs, ad platforms, shipping, payments, internal systems) that don't have a ready-made AI integration and need someone to build one deliberately.

See it in action

1. One-time login: run the authorize command, sign in with Google in the browser that opens, and approve access.

2. Ask Claude: "Search my inbox for anything from [sender] this week" — it searches, nothing else.

3. Ask: "Check my inbox and tell me if anything looks urgent" — it pulls a fast summary of recent mail and reasons over it.

4. Ask: "Draft a reply to that saying I'll follow up tomorrow" — a real draft appears in Gmail. Nothing has been sent.

5. Only if you then say so, ask Claude to send it — that's the one deliberate, irreversible step in the whole flow.

Under the hood

Tools

Setup

1. Install dependencies (requires Python 3.10+; this repo uses uv):

   uv sync

2. Set up Google OAuth and authorize an account — follow workflows/setup_google_oauth.md. Short version:

   cp .env.example .env
   python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"
   # paste the output into .env as TOKEN_ENCRYPTION_KEY
   # download credentials.json from Google Cloud Console into the project root
   python -m tools.gmail_mcp.authorize personal

3. Point Claude Desktop/Code at the server. Add to your MCP client config (e.g. claude_desktop_config.json):

   {
     "mcpServers": {
       "gmail": {
         "command": "/absolute/path/to/mcp-business-tools/.venv/bin/python",
         "args": ["-m", "tools.gmail_mcp.server"],
         "cwd": "/absolute/path/to/mcp-business-tools"
       }
     }
   }

4. Restart Claude Desktop/Code so it picks up the new server.

Adding more accounts

See workflows/add_gmail_account.md.

Project layout

workflows/            SOPs: OAuth setup, adding accounts, inbox-summary pattern
tools/gmail_mcp/       the MCP server package
  config.py            env-driven settings, scopes
  auth.py              OAuth flow + encrypted token storage
  gmail_client.py       Gmail API wrapper functions
  server.py             MCP tool definitions
  authorize.py           one-time per-account OAuth CLI
tokens/                encrypted per-account tokens (gitignored)