Google Calendar AutoAuth MCP Server

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

Features

• Create calendar events with title, description, location, and attendees

• Update existing calendar events

• Delete calendar events

• Retrieve event details

• List events within a specified time range

• Search for events by keyword

• List all available calendars

• Support for natural language date/time input (e.g., "tomorrow at 2pm", "next monday")

• Full integration with Google Calendar 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 Google Calendar Integration Server for Claude Desktop automatically via Smithery:

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 Google Calendar 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 .calendar-mcp folder mkdir -p ~/.calendar-mcp mv gcp-oauth.keys.json ~/.calendar-mcp/ # Run authentication from anywhere npx @nchufa/calendar auth

   b. Local Authentication:

   # Place gcp-oauth.keys.json in your current directory # The file will be automatically copied to global config npx @nchufa/calendar auth

   The authentication process will:

   • Look for gcp-oauth.keys.json in the current directory or ~/.calendar-mcp/

   • If found in current directory, copy it to ~/.calendar-mcp/

   • Open your default browser for Google authentication

   • Save credentials as ~/.calendar-mcp/credentials.json

   Note:

   • After successful authentication, credentials are stored globally in ~/.calendar-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:

Add the following to your Claude Desktop configuration file:

Available Tools

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

1. Create Event (create_event)

Creates a new calendar event.

Natural language date/time is also supported:

2. Get Event (get_event)

Retrieves details of a specific calendar event.

3. Update Event (update_event)

Updates an existing calendar event.

4. Delete Event (delete_event)

Deletes a calendar event.

5. List Events (list_events)

Lists calendar events within a specified time range.

6. Search Events (search_events)

Searches for events matching a query.

7. List Calendars (list_calendars)

Lists all available calendars.

Natural Language Date/Time Support

The server supports various natural language formats for dates and times:

• Specific dates: "2025-04-01T14:00:00" (ISO format)

• Simple references: "today", "tomorrow", "now"

• Relative times: "2 hours later", "3 days later"

• Day references: "next monday", "next tuesday"

• Combined formats: "tomorrow at 2pm", "monday at 15:30"

This makes it easy to create and update events using natural language instructions.

Security Notes

• OAuth credentials are stored securely in your local environment (~/.calendar-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

Troubleshooting

1. OAuth Keys Not Found

   • Make sure gcp-oauth.keys.json is in either your current directory or ~/.calendar-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

Contributing

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

License

MIT

Acknowledgments

Special thanks to GongRzhe and his Calendar-Autoauth-MCP-Server project which served as a foundation for this implementation.

Support

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