gcal-fast-mcp

Google Calendar MCP server built with FastMCP. Provides 10 tools for calendar management, event CRUD, and availability queries via the Google Calendar API v3.

Setup

1. Google OAuth Credentials

Place your Google Cloud OAuth client credentials at ~/.gcal-mcp/gcp-oauth.keys.json (or in the project directory — they'll be copied automatically).

If you already have a GCP project configured for another Google API (e.g. gmail-fast-mcp), you can reuse the same OAuth client — just enable the Google Calendar API in that project.

2. Authenticate

uv run python -m gcal_fast_mcp auth

This opens a browser for the OAuth flow and saves tokens to ~/.gcal-mcp/credentials.json.

For cloud environments with a custom callback URL:

uv run python -m gcal_fast_mcp auth https://your-domain.com/oauth2callback

3. Run the Server

uv run python -m gcal_fast_mcp

MCP Client Configuration

{
  "mcpServers": {
    "google-calendar": {
      "command": "uv",
      "args": ["--directory", "/path/to/gcal-fast-mcp", "run", "google-calendar-fast-mcp"]
    }
  }
}

Tools

Tool	Description
list_calendars	List all calendars the user has access to
get_calendar	Get details of a specific calendar
list_events	List events within a time range (supports search, recurring expansion)
get_event	Get full details of a single event
create_event	Create a new event with attendees, location, etc.
update_event	Update an existing event (partial updates supported)
delete_event	Delete an event
quick_add	Create an event from natural language (e.g. "Lunch tomorrow at noon")
check_availability	Check free/busy status for one or more calendars

Configuration

Environment variables (prefix GCAL_):

Variable	Default	Description
GCAL_OAUTH_PATH	~/.gcal-mcp/gcp-oauth.keys.json	OAuth client secrets file
GCAL_CREDENTIALS_PATH	~/.gcal-mcp/credentials.json	Saved OAuth tokens
GCAL_DEFAULT_CALENDAR	primary	Default calendar ID
GCAL_MAX_RESULTS	50	Default max events returned

Google Calendar API Scopes

• calendar — Full calendar access
• calendar.events — Event CRUD operations