Google Calendar MCP server

google-calendar-mcp

An MCP server for Google Calendar. One binary, stdio, per-user OAuth against your own Google account.

It answers when — calendars, the events on them, and who is free. What a meeting produces (a recording, a notes document, an attachment) belongs to servers built on the Meet, Docs and Drive APIs.

What makes this one different

Most calendar tooling an LLM reaches for gets three things subtly wrong. This server is built around not getting them wrong, and each is enforced by a test rather than by care:

instant, so it cannot land on the wrong day for anyone west of UTC. Every timed event carries a real IANA zone, not just an offset, because an offset cannot expand a repeating event across a daylight-saving change.

• An all-day event is a date, not a time. It never becomes an

where that zone came from, and whether the list was truncated. A schedule that does not say which Thursday it is showing can be read as any Thursday.

• Every read says what it read. The absolute window, the time zone,

details of still makes someone busy, and an event marked "free" does not. A calendar that could not be read is reported as unknown, never folded into "free".

• Availability is not a list of events. An event you cannot see the

The design, its evidence log and the phase plan are in docs/architecture.md.

Status

Complete and in use: reading, writing, recurrence, availability, calendars, sharing, the resources and the Claude Desktop bundle. The tools are listed below, and the phase plan and what is still owed are in docs/architecture.md §16.

Install

go install github.com/mmedum/google-calendar-mcp/cmd/google-calendar-mcp@latest

Or download an archive from the releases page.

Set up

You need your own Google Cloud project and OAuth client. Nothing deployer-specific is baked into this repository.

docs/gcp-setup.md lists. That file is generated from the code, so it cannot fall behind the tool surface.

1. Create a project and enable the Google Calendar API.
2. Configure the OAuth consent screen and add the scopes

1. Create an OAuth client of type Desktop app and download the JSON.
2. Sign in:

google-calendar-mcp login --client-secret ~/path/to/client_secret.json
google-calendar-mcp doctor

doctor checks the client JSON, the stored token, the granted scopes and whether the API answers, and names what is missing.

Signing in over SSH

The OAuth callback reaches the loopback interface of the machine running login, while your browser is on your own machine. Forward the port first. Use --no-browser: it prints the authorization URL and the exact ssh -L line to run, with the port it actually picked.

Configure your MCP client

{
  "mcpServers": {
    "google-calendar": {
      "command": "google-calendar-mcp",
      "env": {
        "GCAL_CLIENT_SECRET": "/path/to/client_secret.json"
      }
    }
  }
}

Every setting is in docs/configuration.md.

Tools

Shortened. The full README is on GitHub.