Gmail AutoAuth MCP Server

A Model Context Protocol (MCP) server for Gmail integration in Claude Desktop with auto authentication support. This server enables AI assistants to manage Gmail through natural language interactions.

Features

• Send emails with subject, content, attachments, and recipients
• Full support for international characters in subject lines and email content
• Read email messages by ID with advanced MIME structure handling
• View email attachments information (filenames, types, sizes)
• Search emails with various criteria (subject, sender, date range)
• List all available Gmail labels (system and user-defined)
• List emails in inbox, sent, or custom labels
• Mark emails as read/unread
• Move emails to different labels/folders
• Delete emails
• Batch operations for efficiently processing multiple emails at once
• Full integration with Gmail API
• Simple OAuth2 authentication flow with auto browser launch
• Support for both Desktop and Web application credentials
• Global credential storage for convenience

Installation & Authentication

Installing via Smithery

To install Gmail AutoAuth for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @gongrzhe/server-gmail-autoauth-mcp --client claude

Installing Manually

1. Create a Google Cloud Project and obtain credentials:

   a. Create a Google Cloud Project:

   • Go to Google Cloud Console
   • Create a new project or select an existing one
   • Enable the Gmail API for your project

   b. Create OAuth 2.0 Credentials:

   • Go to "APIs & Services" > "Credentials"
   • Click "Create Credentials" > "OAuth client ID"
   • Choose either "Desktop app" or "Web application" as application type
   • Give it a name and click "Create"
   • For Web application, add http://localhost:3000/oauth2callback to the authorized redirect URIs
   • Download the JSON file of your client's OAuth keys
   • Rename the key file to gcp-oauth.keys.json

2. Run Authentication:

   You can authenticate in two ways:

   a. Global Authentication (Recommended):

   # First time: Place gcp-oauth.keys.json in your home directory's .gmail-mcp folder
   mkdir -p ~/.gmail-mcp
   mv gcp-oauth.keys.json ~/.gmail-mcp/
   
   # Run authentication from anywhere
   npx @gongrzhe/server-gmail-autoauth-mcp auth

   b. Local Authentication:

   # Place gcp-oauth.keys.json in your current directory
   # The file will be automatically copied to global config
   npx @gongrzhe/server-gmail-autoauth-mcp auth

   The authentication process will:

   • Look for gcp-oauth.keys.json in the current directory or ~/.gmail-mcp/
   • If found in current directory, copy it to ~/.gmail-mcp/
   • Open your default browser for Google authentication
   • Save credentials as ~/.gmail-mcp/credentials.json

   Note:

   • After successful authentication, credentials are stored globally in ~/.gmail-mcp/ and can be used from any directory
   • Both Desktop app and Web application credentials are supported
   • For Web application credentials, make sure to add http://localhost:3000/oauth2callback to your authorized redirect URIs

3. Configure in Claude Desktop:

{
  "mcpServers": {
    "gmail": {
      "command": "npx",
      "args": [
        "@gongrzhe/server-gmail-autoauth-mcp"
      ]
    }
  }
}

Docker Support

If you prefer using Docker:

1. Authentication:

docker run -i --rm \
  --mount type=bind,source=/path/to/gcp-oauth.keys.json,target=/gcp-oauth.keys.json \
  -v mcp-gmail:/gmail-server \
  -e GMAIL_OAUTH_PATH=/gcp-oauth.keys.json \
  -e "GMAIL_CREDENTIALS_PATH=/gmail-server/credentials.json" \
  -p 3000:3000 \
  mcp/gmail auth

2. Usage:

{
  "mcpServers": {
    "gmail": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-v",
        "mcp-gmail:/gmail-server",
        "-e",
        "GMAIL_CREDENTIALS_PATH=/gmail-server/credentials.json",
        "mcp/gmail"
      ]
    }
  }
}

Cloud Server Authentication

For cloud server environments (like n8n), you can specify a custom callback URL during authentication:

npx @gongrzhe/server-gmail-autoauth-mcp auth https://gmail.gongrzhe.com/oauth2callback

Setup Instructions for Cloud Environment

1. Configure Reverse Proxy:

   • Set up your n8n container to expose a port for authentication
   • Configure a reverse proxy to forward traffic from your domain (e.g., gmail.gongrzhe.com) to this port

2. DNS Configuration:

   • Add an A record in your DNS settings to resolve your domain to your cloud server's IP address

3. Google Cloud Platform Setup:

   • In your Google Cloud Console, add your custom domain callback URL (e.g., https://gmail.gongrzhe.com/oauth2callback) to the authorized redirect URIs list

4. Run Authentication:

   npx @gongrzhe/server-gmail-autoauth-mcp auth https://gmail.gongrzhe.com/oauth2callback

5. Configure in your application:

   {
     "mcpServers": {
       "gmail": {
         "command": "npx",
         "args": [
           "@gongrzhe/server-gmail-autoauth-mcp"
         ]
       }
     }
   }

This approach allows authentication flows to work properly in environments where localhost isn't accessible, such as containerized applications or cloud servers.

Available Tools

The server provides the following tools that can be used through Claude Desktop:

1. Send Email (send_email)

Sends a new email immediately.

{
  "to": ["recipient@example.com"],
  "subject": "Meeting Tomorrow",
  "body": "Hi,\n\nJust a reminder about our meeting tomorrow at 10 AM.\n\nBest regards",
  "cc": ["cc@example.com"],
  "bcc": ["bcc@example.com"]
}

2. Draft Email (draft_email)

Creates a draft email without sending it.

{
  "to": ["recipient@example.com"],
  "subject": "Draft Report",
  "body": "Here's the draft report for your review.",
  "cc": ["manager@example.com"]
}

3. Read Email (read_email)

Retrieves the content of a specific email by its ID.

{
  "messageId": "182ab45cd67ef"
}

4. Search Emails (search_emails)

Searches for emails using Gmail search syntax.

{
  "query": "from:sender@example.com after:2024/01/01 has:attachment",
  "maxResults": 10
}

5. Modify Email (modify_email)

Adds or removes labels from emails (move to different folders, archive, etc.).

{
  "messageId": "182ab45cd67ef",
  "addLabelIds": ["IMPORTANT"],
  "removeLabelIds": ["INBOX"]
}

6. Delete Email (delete_email)

Permanently deletes an email.

{
  "messageId": "182ab45cd67ef"
}

7. List Email Labels (list_email_labels)

Retrieves all available Gmail labels.

{}

8. Batch Modify Emails (batch_modify_emails)

Modifies labels for multiple emails in efficient batches.

{
  "messageIds": ["182ab45cd67ef", "182ab45cd67eg", "182ab45cd67eh"],
  "addLabelIds": ["IMPORTANT"],
  "removeLabelIds": ["INBOX"],
  "batchSize": 50
}

9. Batch Delete Emails (batch_delete_emails)

Permanently deletes multiple emails in efficient batches.

{
  "messageIds": ["182ab45cd67ef", "182ab45cd67eg", "182ab45cd67eh"],
  "batchSize": 50
}

Advanced Search Syntax

The search_emails tool supports Gmail's powerful search operators:

Operator	Example	Description
from:	from:john@example.com	Emails from a specific sender
to:	to:mary@example.com	Emails sent to a specific recipient
subject:	subject:"meeting notes"	Emails with specific text in the subject
has:attachment	has:attachment	Emails with attachments
after:	after:2024/01/01	Emails received after a date
before:	before:2024/02/01	Emails received before a date
is:	is:unread	Emails with a specific state
label:	label:work	Emails with a specific label

You can combine multiple operators: from:john@example.com after:2024/01/01 has:attachment

Advanced Features

Email Content Extraction

The server intelligently extracts email content from complex MIME structures:

• Prioritizes plain text content when available
• Falls back to HTML content if plain text is not available
• Handles multi-part MIME messages with nested parts
• Processes attachments information (filename, type, size)
• Preserves original email headers (From, To, Subject, Date)

International Character Support

The server fully supports non-ASCII characters in email subjects and content, including:

• Turkish, Chinese, Japanese, Korean, and other non-Latin alphabets
• Special characters and symbols
• Proper encoding ensures correct display in email clients

Batch Operations

The server includes efficient batch processing capabilities:

• Process up to 50 emails at once (configurable batch size)
• Automatic chunking of large email sets to avoid API limits
• Detailed success/failure reporting for each operation
• Graceful error handling with individual retries
• Perfect for bulk inbox management and organization tasks

Security Notes

• OAuth credentials are stored securely in your local environment (~/.gmail-mcp/)
• The server uses offline access to maintain persistent authentication
• Never share or commit your credentials to version control
• Regularly review and revoke unused access in your Google Account settings
• Credentials are stored globally but are only accessible by the current user

Troubleshooting

1. OAuth Keys Not Found

   • Make sure gcp-oauth.keys.json is in either your current directory or ~/.gmail-mcp/
   • Check file permissions

2. Invalid Credentials Format

   • Ensure your OAuth keys file contains either web or installed credentials
   • For web applications, verify the redirect URI is correctly configured

3. Port Already in Use

   • If port 3000 is already in use, please free it up before running authentication
   • You can find and stop the process using that port

4. Batch Operation Failures

   • If batch operations fail, they automatically retry individual items
   • Check the detailed error messages for specific failures
   • Consider reducing the batch size if you encounter rate limiting

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT

Support

If you encounter any issues or have questions, please file an issue on the GitHub repository.