Multi-Google MCP

Connect multiple Google accounts to Claude Code at the same time. Read Gmail, send email, and manage Google Calendar across any number of accounts — personal, work, school, whatever.

Claude Code's built-in Google integrations only connect one account at a time. This is a local MCP server that fixes that.

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What You Get

Eleven tools, all of which take an account parameter so Claude knows which Google account to use:

Gmail

• gmail_search — search emails using Gmail query syntax
• gmail_read — read a specific email by ID
• gmail_send — send an email
• gmail_draft — create a draft
• gmail_list_labels — list all Gmail labels

Calendar

• calendar_list_events — list upcoming events
• calendar_create_event — create an event
• calendar_update_event — update an existing event
• calendar_delete_event — delete an event
• calendar_list_calendars — list all calendars in the account

Utility

• google_list_accounts — list all connected accounts

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Quick Start (with Claude Code)

The fastest way to set this up is to let Claude Code walk you through it. Clone this repo, open the folder in Claude Code, and run the skill:

/setup-multi-google

Claude Code will handle the install, guide you through the Google Cloud Console setup, and verify everything works. This is the recommended path if you're new to any of this.

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Manual Setup

If you'd rather run the steps yourself, here's the full process.

Prerequisites

• Node.js v18 or newer — check with node --version. If you don't have it, install from nodejs.org or with Homebrew: brew install node
• Claude Code — installed and working
• A Google account (or several) that you want to connect

Step 1: Install

git clone https://github.com/chaymore/multi-google-mcp.git ~/multi-google-mcp
cd ~/multi-google-mcp
npm install

Step 2: Create Google OAuth Credentials

You only need to do this once, even if you're connecting multiple accounts. It takes about 3 minutes.

1. Go to console.cloud.google.com
2. Create a new project: click the project dropdown at the top → "New Project" → name it "Claude MCP" → Create
3. Enable the APIs: go to APIs & Services → Library, search for Gmail API, click it, click Enable. Repeat for Google Calendar API.
4. Configure the consent screen: go to APIs & Services → OAuth consent screen → External → Create. Fill in:
   • App name: "Claude MCP" (or whatever)
   • User support email: your email
   • Developer contact email: your email
   • Click Save and Continue through the remaining pages
   • On the Test users page, click + Add Users and add every Google email address you plan to connect. This is required while the app is in "Testing" mode.
5. Create the credentials: go to APIs & Services → Credentials → Create Credentials → OAuth client ID → Application type: Desktop app → Create. Copy the Client ID and Client Secret — you'll paste them in the next step.

Step 3: Run the Setup Script

npm run setup

This will:

1. Ask you to paste your Client ID and Client Secret
2. Ask for a label for your first account (e.g. personal, work)
3. Open your browser to sign in to Google
4. Ask if you want to add another account

When Google shows the "This app isn't verified" warning: click Advanced → Go to Claude MCP (unsafe). It's your own app, so this is safe. Google shows this warning for every personal-use app that isn't publicly listed.

When the script finishes, it automatically builds the project and registers the MCP server in Claude Code's settings.

Step 4: Restart Claude Code

Close and reopen Claude Code so it picks up the new MCP server. The multi-google tools will be available in any new session.

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Adding More Accounts Later

To connect another Google account after the initial setup:

cd ~/multi-google-mcp
npm run add-account

Give it a new label, click through the Google sign-in, and restart Claude Code. You can connect as many accounts as you want.

Don't forget: before the new account can sign in, you need to add its email address to the Test users list in the OAuth consent screen of your Google Cloud project. Otherwise Google will block the sign-in with a "this app hasn't completed verification" error.

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Usage

Once the server is connected, you can use natural language in Claude Code:

• "Search my personal Gmail for emails from Kristen this week"
• "Read the top email in my work inbox"
• "Create a calendar event on my work calendar for Friday at 3pm called Team Sync"
• "Draft an email to caleb@example.com from my personal account"

Claude Code will pick the right tool and use the account label you specified.

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Troubleshooting

"This app hasn't completed the Google verification process" You're trying to sign in with a Google account that isn't added as a test user. Go to APIs & Services → OAuth consent screen, scroll to Test users, click + Add Users, add the email, and save. Then re-run npm run add-account.

"Port 3847 is already in use" Something else is using the port the OAuth flow needs. Find it with lsof -i :3847 and close it, then try again.

"Authentication expired for account X" Your tokens expired or were revoked. Run npm run add-account and use the same label to re-authenticate.

Tools don't show up in Claude Code Make sure you restarted Claude Code after setup. You can verify the server is registered by checking ~/.claude/settings.json — you should see a multi-google entry under mcpServers.

"No authorization code received" You probably closed the browser tab too early, or denied permissions. Re-run npm run add-account and complete the sign-in all the way through.

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How It Works

The server runs locally on your machine. It stores OAuth tokens in ~/.config/multi-google-mcp/config.json with file permissions set to 0600 (only you can read it). Tokens are refreshed automatically when they expire.

Each tool takes an account parameter — when you call gmail_search with account: "work", the server loads the tokens for the "work" account, builds an authenticated Google API client, and runs the search. Nothing leaves your machine except the direct API calls to Google.

Don't publish your Google Cloud project to production — keep it in "Testing" mode. Testing mode allows up to 100 test users and your refresh tokens won't expire prematurely, which is exactly what you want for personal use.

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Security Notes

• Your OAuth tokens are stored locally in ~/.config/multi-google-mcp/config.json. Don't commit this file or share it.
• The server runs locally and only communicates with Google's APIs. No third-party services are involved.
• The scopes requested are: Gmail modify/compose/labels, and Calendar read/write. If you want to reduce these, edit SCOPES in src/config.ts and re-run setup.
• Revoke access any time at myaccount.google.com/permissions.