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 attachment support - send and receive file attachments
• Download email attachments to local filesystem
• Support for HTML emails and multipart messages with both HTML and plain text versions
• Full support for international characters in subject lines and email content
• Read email messages by ID with advanced MIME structure handling
• Enhanced attachment display showing filenames, types, sizes, and download IDs
• Search emails with various criteria (subject, sender, date range)
• Comprehensive label management with ability to create, update, delete and list labels
• 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

Most users should not create their own Google OAuth client. Choose one of these flows:

• Zero-setup (recommended for end users): the maintainer provides an OAuth client bundled with the app. Users just run the auth command.
• BYO keys (advanced): power users can still supply their own gcp-oauth.keys.json.

Zero-setup (maintainer-provided client)

• By default, the server fetches the OAuth client from https://api.todofor.ai/gmail-oauth.json
• You can override this by setting GMAIL_OAUTH_URL to your own hosted JSON

End users:

# Just run auth (uses bundled client)
npx @todoforai/server-gmail-autoauth-mcp auth

The first successful auth stores tokens at ~/.gmail-mcp/credentials.json for future use.

BYO keys (optional)

If you prefer your own keys:

• Put gcp-oauth.keys.json in the current dir or ~/.gmail-mcp/
• Or set GMAIL_OAUTH_PATH to the file
• Or set GMAIL_OAUTH_URL to a hosted JSON

npx @todoforai/server-gmail-autoauth-mcp auth

3. Configure in Claude Desktop:

{
  "mcpServers": {
    "gmail": {
      "command": "npx",
      "args": [
        "@todoforai/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 @todoforai/server-gmail-autoauth-mcp auth https://gmail.todofor.ai/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 @todoforai/server-gmail-autoauth-mcp auth https://gmail.todofor.ai/oauth2callback

5. Configure in your application:

   {
     "mcpServers": {
       "gmail": {
         "command": "npx",
         "args": [
           "@todoforai/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. Supports plain text, HTML, or multipart emails with optional file attachments.

Basic Email:

{
  "to": ["[email protected]"],
  "subject": "Meeting Tomorrow",
  "body": "Hi,\n\nJust a reminder about our meeting tomorrow at 10 AM.\n\nBest regards",
  "cc": ["[email protected]"],
  "bcc": ["[email protected]"],
  "mimeType": "text/plain"
}

Email with Attachments:

{
  "to": ["[email protected]"],
  "subject": "Project Files",
  "body": "Hi,\n\nPlease find the project files attached.\n\nBest regards",
  "attachments": [
    "/path/to/document.pdf",
    "/path/to/spreadsheet.xlsx",
    "/path/to/presentation.pptx"
  ]
}

HTML Email Example:

{
  "to": ["[email protected]"],
  "subject": "Meeting Tomorrow",
  "mimeType": "text/html",
  "body": "<html><body><h1>Meeting Reminder</h1><p>Just a reminder about our <b>meeting tomorrow</b> at 10 AM.</p><p>Best regards</p></body></html>"
}

Multipart Email Example (HTML + Plain Text):

{
  "to": ["[email protected]"],
  "subject": "Meeting Tomorrow",
  "mimeType": "multipart/alternative",
  "body": "Hi,\n\nJust a reminder about our meeting tomorrow at 10 AM.\n\nBest regards",
  "htmlBody": "<html><body><h1>Meeting Reminder</h1><p>Just a reminder about our <b>meeting tomorrow</b> at 10 AM.</p><p>Best regards</p></body></html>"
}

2. Draft Email (draft_email)

Creates a draft email without sending it. Also supports attachments.

{
  "to": ["[email protected]"],
  "subject": "Draft Report",
  "body": "Here's the draft report for your review.",
  "cc": ["[email protected]"],
  "attachments": ["/path/to/draft_report.docx"]
}

3. Read Email (read_email)

Retrieves the content of a specific email by its ID. Now shows enhanced attachment information.

{
  "messageId": "182ab45cd67ef"
}

Enhanced Response includes attachment details:

Subject: Project Files
From: [email protected]
To: [email protected]
Date: Thu, 19 Jun 2025 10:30:00 -0400

Email body content here...

Attachments (2):
- document.pdf (application/pdf, 245 KB, ID: ANGjdJ9fkTs-i3GCQo5o97f_itG...)
- spreadsheet.xlsx (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, 89 KB, ID: BWHkeL8gkUt-j4HDRp6o98g_juI...)

4. Download Attachment (download_attachment)

NEW: Downloads email attachments to your local filesystem.

{
  "messageId": "182ab45cd67ef",
  "attachmentId": "ANGjdJ9fkTs-i3GCQo5o97f_itG...",
  "savePath": "/path/to/downloads",
  "filename": "downloaded_document.pdf"
}

Parameters:

• messageId: The ID of the email containing the attachment
• attachmentId: The attachment ID (shown in enhanced email display)
• savePath: Directory to save the file (optional, defaults to current directory)
• filename: Custom filename (optional, uses original filename if not provided)

5. Search Emails (search_emails)

Searches for emails using Gmail search syntax.

{
  "query": "from:[email protected] after:2024/01/01 has:attachment",
  "maxResults": 10
}

6. Modify Email (modify_email)

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

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

7. Delete Email (delete_email)

Permanently deletes an email.

{
  "messageId": "182ab45cd67ef"
}

8. List Email Labels (list_email_labels)

Retrieves all available Gmail labels.

{}

9. Create Label (create_label)

Creates a new Gmail label.

{
  "name": "Important Projects",
  "messageListVisibility": "show",
  "labelListVisibility": "labelShow"
}

10. Update Label (update_label)

Updates an existing Gmail label.

{
  "id": "Label_1234567890",
  "name": "Urgent Projects",
  "messageListVisibility": "show",
  "labelListVisibility": "labelShow"
}

11. Delete Label (delete_label)

Deletes a Gmail label.

{
  "id": "Label_1234567890"
}

12. Get or Create Label (get_or_create_label)

Gets an existing label by name or creates it if it doesn't exist.

{
  "name": "Project XYZ",
  "messageListVisibility": "show",
  "labelListVisibility": "labelShow"
}

13. Batch Modify Emails (batch_modify_emails)

Modifies labels for multiple emails in efficient batches.

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

14. Batch Delete Emails (batch_delete_emails)

Permanently deletes multiple emails in efficient batches.

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

14. Create Filter (create_filter)

Creates a new Gmail filter with custom criteria and actions.

{
  "criteria": {
    "from": "[email protected]",
    "hasAttachment": false
  },
  "action": {
    "addLabelIds": ["Label_Newsletter"],
    "removeLabelIds": ["INBOX"]
  }
}

15. List Filters (list_filters)

Retrieves all Gmail filters.

{}

16. Get Filter (get_filter)

Gets details of a specific Gmail filter.

{
  "filterId": "ANe1Bmj1234567890"
}

17. Delete Filter (delete_filter)

Deletes a Gmail filter.

{
  "filterId": "ANe1Bmj1234567890"
}

18. Create Filter from Template (create_filter_from_template)

Creates a filter using pre-defined templates for common scenarios.

{
  "template": "fromSender",
  "parameters": {
    "senderEmail": "[email protected]",
    "labelIds": ["Label_GitHub"],
    "archive": true
  }
}

Filter Management Features

Filter Criteria

You can create filters based on various criteria:

| Criteria | Example | Description | |----------|---------|-------------| | from | "[email protected]" | Emails from a specific sender | | to | "[email protected]" | Emails sent to a specific recipient | | subject | "Meeting" | Emails with specific text in subject | | query | "has:attachment" | Gmail search query syntax | | negatedQuery | "spam" | Text that must NOT be present | | hasAttachment | true | Emails with attachments | | size | 10485760 | Email size in bytes | | sizeComparison | "larger" | Size comparison (larger, smaller) |

Filter Actions

Filters can perform the following actions:

| Action | Example | Description | |--------|---------|-------------| | addLabelIds | ["IMPORTANT", "Label_Work"] | Add labels to matching emails | | removeLabelIds | ["INBOX", "UNREAD"] | Remove labels from matching emails | | forward | "[email protected]" | Forward emails to another address |

Filter Templates

The server includes pre-built templates for common filtering scenarios:

1. From Sender Template (fromSender)

Filters emails from a specific sender and optionally archives them.

{
  "template": "fromSender",
  "parameters": {
    "senderEmail": "[email protected]",
    "labelIds": ["Label_Newsletter"],
    "archive": true
  }
}

2. Subject Filter Template (withSubject)

Filters emails with specific subject text and optionally marks as read.

{
  "template": "withSubject",
  "parameters": {
    "subjectText": "[URGENT]",
    "labelIds": ["Label_Urgent"],
    "markAsRead": false
  }
}

3. Attachment Filter Template (withAttachments)

Filters all emails with attachments.

{
  "template": "withAttachments",
  "parameters": {
    "labelIds": ["Label_Attachments"]
  }
}

4. Large Email Template (largeEmails)

Filters emails larger than a specified size.

{
  "template": "largeEmails",
  "parameters": {
    "sizeInBytes": 10485760,
    "labelIds": ["Label_Large"]
  }
}

5. Content Filter Template (containingText)

Filters emails containing specific text and optionally marks as important.

{
  "template": "containingText",
  "parameters": {
    "searchText": "invoice",
    "labelIds": ["Label_Finance"],
    "markImportant": true
  }
}

6. Mailing List Template (mailingList)

Filters mailing list emails and optionally archives them.

{
  "template": "mailingList",
  "parameters": {
    "listIdentifier": "dev-team",
    "labelIds": ["Label_DevTeam"],
    "archive": true
  }
}

Common Filter Examples

Here are some practical filter examples:

Auto-organize newsletters:

{
  "criteria": {
    "from": "[email protected]"
  },
  "action": {
    "addLabelIds": ["Label_Newsletter"],
    "removeLabelIds": ["INBOX"]
  }
}

Handle promotional emails:

{
  "criteria": {
    "query": "unsubscribe OR promotional"
  },
  "action": {
    "addLabelIds": ["Label_Promotions"],
    "removeLabelIds": ["INBOX", "UNREAD"]
  }
}

Priority emails from boss:

{
  "criteria": {
    "from": "[email protected]"
  },
  "action": {
    "addLabelIds": ["IMPORTANT", "Label_Boss"]
  }
}

Large attachments:

{
  "criteria": {
    "size": 10485760,
    "sizeComparison": "larger",
    "hasAttachment": true
  },
  "action": {
    "addLabelIds": ["Label_LargeFiles"]
  }
}

Advanced Search Syntax

The search_emails tool supports Gmail's powerful search operators:

| Operator | Example | Description | |----------|---------|-------------| | from: | from:[email protected] | Emails from a specific sender | | to: | to:[email protected] | 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:[email protected] after:2024/01/01 has:attachment

Advanced Features

Email Attachment Support

The server provides comprehensive attachment functionality:

• Sending Attachments: Include file paths in the attachments array when sending or drafting emails
• Attachment Detection: Automatically detects MIME types and file sizes
• Download Capability: Download any email attachment to your local filesystem
• Enhanced Display: View detailed attachment information including filenames, types, sizes, and download IDs
• Multiple Formats: Support for all common file types (documents, images, archives, etc.)
• RFC822 Compliance: Uses Nodemailer for proper MIME message formatting

Supported File Types: All standard file types including PDF, DOCX, XLSX, PPTX, images (PNG, JPG, GIF), archives (ZIP, RAR), and more.

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, download ID)
• 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

Comprehensive Label Management

The server provides a complete set of tools for managing Gmail labels:

• Create Labels: Create new labels with customizable visibility settings
• Update Labels: Rename labels or change their visibility settings
• Delete Labels: Remove user-created labels (system labels are protected)
• Find or Create: Get a label by name or automatically create it if not found
• List All Labels: View all system and user labels with detailed information
• Label Visibility Options: Control how labels appear in message and label lists

Label visibility settings include:

• messageListVisibility: Controls whether the label appears in the message list (show or hide)
• labelListVisibility: Controls how the label appears in the label list (labelShow, labelShowIfUnread, or labelHide)

These label management features enable sophisticated organization of emails directly through Claude, without needing to switch to the Gmail interface.

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
• Attachment files are processed locally and never stored permanently by the server

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

5. Attachment Issues

   • File Not Found: Ensure attachment file paths are correct and accessible
   • Permission Errors: Check that the server has read access to attachment files
   • Size Limits: Gmail has a 25MB attachment size limit per email
   • Download Failures: Verify you have write permissions to the download directory

Contributing

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

Running evals

The evals package loads an mcp client that then runs the index.ts file, so there is no need to rebuild between tests. You can load environment variables by prefixing the npx command. Full documentation can be found here.

OPENAI_API_KEY=your-key  npx mcp-eval src/evals/evals.ts src/index.ts

License

MIT

Support

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