google-calendar-mcp

MCP server for Google Calendar: list/create/update/delete events, quick-add from natural language, respond to invitations, and check free/busy availability across one or more accounts.

Why not the official Google Calendar MCP connector?

Google has started offering official remote MCP servers per Workspace app (Gmail, Sheets, Docs, Drive, Calendar). The Calendar one is convenient but, as of writing, ties one Google account to one connector authorization — if you need several independent Google identities available as separate MCP servers at the same time, you need one token per account, which this self-hosted server supports natively.

Tools (9)

Tool	What it does
list_calendars	List all calendars the account can access (id, name, whether it's primary)
list_events	List events in a date range, optional free-text filter
get_event	Full detail of one event
create_event	Create an event (supports all-day and attendees)
quick_add_event	Create an event from natural language (e.g. "Meeting tomorrow at 10am")
update_event	Update only the fields you pass on an existing event
respond_to_event	Accept/decline/mark tentative on an invitation
delete_event	Delete an event — destructive, requires confirmed=True
check_availability	Free/busy query across one or more calendars in a time range

Setup

1. Create a Google Cloud project (or reuse one) and enable the Google Calendar API.
2. Create an OAuth 2.0 Client ID of type "Desktop app" and download it as client_secret.json.
3. If the app is in "Testing" mode, add your Google account(s) as test users.
4. Install dependencies:

   python3 -m venv .venv
   source .venv/bin/activate
   pip install -r requirements.txt
   

5. Run the OAuth flow once per account you want to expose:

   CLIENT_SECRET_PATH=~/.config/google-calendar-mcp/client_secret.json \
     python3 setup_auth.py personal
   

   This opens a browser — log in and grant access. The token is saved to ~/.config/google-calendar-mcp/token_personal.json. Repeat with a different account label for each additional identity.

MCP client configuration

{
  "mcpServers": {
    "google-calendar": {
      "command": "/path/to/.venv/bin/python3",
      "args": ["/path/to/google-calendar-mcp/server.py"],
      "env": {
        "GOOGLE_CALENDAR_TOKEN_PATH": "~/.config/google-calendar-mcp/token_personal.json"
      }
    }
  }
}

To expose a second account, add another entry pointing at the same server.py with a different GOOGLE_CALENDAR_TOKEN_PATH.

Env var	Purpose
GOOGLE_CALENDAR_TOKEN_PATH	Path to the OAuth token for this account

Notes

• create_event/update_event detect an all-day event automatically when start/end are a bare YYYY-MM-DD date instead of a full ISO 8601 timestamp.
• delete_event follows a confirm-first pattern: without confirmed=True it returns the event summary and a requires_confirmation: true flag instead of deleting anything.
• respond_to_event looks for the attendee entry flagged as self in the event's attendee list — you don't need to pass the account's own email.

License

MIT — see LICENSE.