Gmail Mcp Multiauth

A Gmail MCP server that actually supports multiple accounts. Fork of the archived GongRzhe/Gmail-MCP-Server with two fixes the original never shipped:

1. Token refresh persistence — refreshed OAuth tokens are saved back to disk. Without this, each account silently loses auth after the first token expiry.
2. Account isolation — each server instance knows which account it is via GMAIL_ACCOUNT_NAME. The MCP server name becomes gmail-personal, gmail-business, etc. instead of all four showing as gmail.

Works with Claude Desktop, Cursor, or any MCP-compatible client.

Setup

1. Google Cloud credentials

You need a gcp-oauth.keys.json for each account — or one shared OAuth app with separate tokens. The simplest approach: one Google Cloud project, one OAuth client, one gcp-oauth.keys.json file used by all accounts.

1. Go to Google Cloud Console
2. Create a project → Enable the Gmail API
3. Create OAuth 2.0 credentials (Desktop app type)
4. Download as gcp-oauth.keys.json

2. Create per-account directories

mkdir -p ~/.gmail-personal ~/.gmail-business ~/.gmail-newsletter ~/.gmail-payments

Copy your gcp-oauth.keys.json into each:

cp gcp-oauth.keys.json ~/.gmail-personal/
cp gcp-oauth.keys.json ~/.gmail-business/
# repeat for each account

3. Run setup for each account

One command per account. It opens a browser, you sign in with the right Google account, and it creates everything automatically.

# The second argument is where your downloaded keys file is right now.
# It gets copied into ~/.gmail-personal/ — Downloads is not used after this.
npx gmail-mcp-multiauth setup personal ~/Downloads/gcp-oauth.keys.json
npx gmail-mcp-multiauth setup work     ~/Downloads/gcp-oauth.keys.json
npx gmail-mcp-multiauth setup client   ~/Downloads/gcp-oauth.keys.json

After each command, these files exist in their own folder:

~/.gmail-personal/
  gcp-oauth.keys.json   ← copied from your download
  credentials.json      ← written after you authenticate
  start-mcp.sh          ← generated, ready to use

The setup command also prints the exact JSON block to paste into your MCP config.

4. Add to your MCP config

Cursor (~/.cursor/mcp.json) or Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "gmail-personal": {
      "command": "/Users/YOUR_NAME/.gmail-personal/start-mcp.sh",
      "args": []
    },
    "gmail-business": {
      "command": "/Users/YOUR_NAME/.gmail-business/start-mcp.sh",
      "args": []
    }
  }
}

Restart your client. Each account shows up as a separate MCP server with its own name.

Environment variables

What it can do

• Send, draft, read, search emails
• Attachments (send and download)
• Label management (create, update, delete, list)
• Gmail filters
• Batch operations (mark read, move, delete)
• HTML emails

Single-account setup

If you only need one account, skip the wrapper scripts and configure directly:

{
  "mcpServers": {
    "gmail": {
      "command": "npx",
      "args": ["-y", "@jessicaoy89/gmail-mcp"],
      "env": {
        "GMAIL_OAUTH_PATH": "/Users/YOU/.gmail/gcp-oauth.keys.json",
        "GMAIL_CREDENTIALS_PATH": "/Users/YOU/.gmail/credentials.json",
        "GMAIL_ACCOUNT_NAME": "main"
      }
    }
  }
}

Credit

Originally built by GongRzhe. Forked and maintained here after the original was archived in March 2026.