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Google Calendar MCP Server

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MCP server for the Google Calendar API: events, recurrence, invitations, availability, calendars.

About

MCP server for the Google Calendar API: events, recurrence, invitations, availability, calendars.

Security Report

10.0
Low Risk10.0Low Risk

Valid MCP server (1 strong, 1 medium validity signals). No known CVEs in dependencies. Package registry verified. Imported from the Official MCP Registry. Trust signals: trusted author (13/13 approved).

4 files analyzed · 1 issue found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

HTTP Network Access

Connects to external APIs or services over the internet.

What You'll Need

Set these up before or after installing:

Google OAuth2 client id (refresh-token flow).Optional

Environment variable: GOOGLE_CALENDAR_CLIENT_ID

Google OAuth2 client secret (refresh-token flow). Treat it as a secret.Required

Environment variable: GOOGLE_CALENDAR_CLIENT_SECRET

Google OAuth2 refresh token, exchanged for access tokens automatically. Treat it as a secret.Required

Environment variable: GOOGLE_CALENDAR_REFRESH_TOKEN

Static OAuth2 access token (~1h lifetime) — alternative to the refresh-token trio, mostly for testing.Required

Environment variable: GOOGLE_CALENDAR_ACCESS_TOKEN

API root override.Optional

Environment variable: GOOGLE_CALENDAR_API_BASE

Per-request timeout in milliseconds.Optional

Environment variable: GOOGLE_CALENDAR_TIMEOUT_MS

Retries on transient errors (429 always; 5xx/network for reads).Optional

Environment variable: GOOGLE_CALENDAR_MAX_RETRIES

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "io-github-a1-x-tech-mcp-google-calendar": {
      "env": {
        "GOOGLE_CALENDAR_API_BASE": "your-google-calendar-api-base-here",
        "GOOGLE_CALENDAR_CLIENT_ID": "your-google-calendar-client-id-here",
        "GOOGLE_CALENDAR_TIMEOUT_MS": "your-google-calendar-timeout-ms-here",
        "GOOGLE_CALENDAR_MAX_RETRIES": "your-google-calendar-max-retries-here",
        "GOOGLE_CALENDAR_ACCESS_TOKEN": "your-google-calendar-access-token-here",
        "GOOGLE_CALENDAR_CLIENT_SECRET": "your-google-calendar-client-secret-here",
        "GOOGLE_CALENDAR_REFRESH_TOKEN": "your-google-calendar-refresh-token-here"
      },
      "args": [
        "-y",
        "@a1-x-tech/mcp-google-calendar"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

Google Calendar MCP

English | Русский

npm CI Glama License: MIT

A1 Google Calendar MCP lets an AI app manage Google Calendar in plain language. Review your week, schedule a meeting with guests and a Google Meet link, reschedule or cancel it, find a slot when everyone is free, and block Out of Office or Focus Time.

It uses the Google Calendar API with your Google account. It distinguishes a whole recurring series from a single occurrence and makes the limits of the Calendar API explicit instead of implying that every calendar task is possible.

  • 13 tools. Inspect calendars, events and free/busy, create and edit events, expand recurring series, and block Out of Office and Focus Time.
  • Nobody is emailed by accident. The Calendar API's default for invitations, changes and cancellations is silence; guests get email only when you ask for it via send_updates.
  • Writes are never replayed. After an ambiguous failure the server does not retry a write — a duplicated event could re-email every guest.
  • Minimal Google scopes. It uses calendar.events and calendar.readonly, without the broad calendar scope.

Start with a read-only question:

What's on my calendar this week? Point out any overlapping meetings.

Connect the server · Explore use cases · Open technical documentation


See it work in a minute

You: What does my Thursday look like, and when are Anna and I both free?

Assistant: Shows Thursday's events and the free slots you share. Nothing changes.

You: Book a 45-minute design review with Anna in the first shared slot, with a Google Meet link.

Assistant: Shows the proposed time, guest list and Meet link, then asks for confirmation before creating the event.

You: Confirm.

Assistant: Creates the event. Nobody gets an email unless you ask it to send invitations.

Contents

Quick start

You need Node.js 20+, a Google account and OAuth credentials from a Google Cloud project with the Google Calendar API enabled.

  1. Prepare Google OAuth access.
  2. Add the server to your AI app.
  3. Ask the read-only question above.

In the app: open Settings → MCP servers, select Add server, choose STDIO, enter the command npx -y @a1-x-tech/mcp-google-calendar@latest and environment variables GOOGLE_CALENDAR_CLIENT_ID, GOOGLE_CALENDAR_CLIENT_SECRET, GOOGLE_CALENDAR_REFRESH_TOKEN, then select Save and Restart.

From the command line:

codex mcp add google-calendar \
  --env GOOGLE_CALENDAR_CLIENT_ID=your_client_id \
  --env GOOGLE_CALENDAR_CLIENT_SECRET=your_client_secret \
  --env GOOGLE_CALENDAR_REFRESH_TOKEN=your_refresh_token \
  -- npx -y @a1-x-tech/mcp-google-calendar@latest
codex mcp list

Codex MCP documentation

claude mcp add \
  --env GOOGLE_CALENDAR_CLIENT_ID=your_client_id \
  --env GOOGLE_CALENDAR_CLIENT_SECRET=your_client_secret \
  --env GOOGLE_CALENDAR_REFRESH_TOKEN=your_refresh_token \
  --transport stdio --scope user google-calendar \
  -- npx -y @a1-x-tech/mcp-google-calendar@latest
claude mcp list

Claude Code MCP documentation

The current official path is Settings → Extensions. For a custom desktop extension, open Advanced settings → Extension Developer → Install Extension…, select a .mcpb file and follow the prompts.

This repository currently publishes an npm stdio package and does not contain a .mcpb bundle. For Claude Desktop builds that still support local configuration, use the following JSON stdio configuration as a fallback:

{
  "mcpServers": {
    "google-calendar": {
      "command": "npx",
      "args": ["-y", "@a1-x-tech/mcp-google-calendar@latest"],
      "env": {
        "GOOGLE_CALENDAR_CLIENT_ID": "your_client_id",
        "GOOGLE_CALENDAR_CLIENT_SECRET": "your_client_secret",
        "GOOGLE_CALENDAR_REFRESH_TOKEN": "your_refresh_token"
      }
    }
  }
}

In those builds, save it to ~/Library/Application Support/Claude/claude_desktop_config.json on macOS or %APPDATA%\Claude\claude_desktop_config.json on Windows.

Claude Desktop MCP documentation

Add this to ~/.cursor/mcp.json on macOS/Linux or %USERPROFILE%\.cursor\mcp.json on Windows:

{
  "mcpServers": {
    "google-calendar": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@a1-x-tech/mcp-google-calendar@latest"],
      "env": {
        "GOOGLE_CALENDAR_CLIENT_ID": "your_client_id",
        "GOOGLE_CALENDAR_CLIENT_SECRET": "your_client_secret",
        "GOOGLE_CALENDAR_REFRESH_TOKEN": "your_refresh_token"
      }
    }
  }
}

Cursor MCP documentation

Run MCP: Open User Configuration and add:

{
  "servers": {
    "google-calendar": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@a1-x-tech/mcp-google-calendar@latest"],
      "env": {
        "GOOGLE_CALENDAR_CLIENT_ID": "${input:calendar_client_id}",
        "GOOGLE_CALENDAR_CLIENT_SECRET": "${input:calendar_client_secret}",
        "GOOGLE_CALENDAR_REFRESH_TOKEN": "${input:calendar_refresh_token}"
      }
    }
  },
  "inputs": [
    { "type": "promptString", "id": "calendar_client_id", "description": "Google OAuth client ID" },
    { "type": "promptString", "id": "calendar_client_secret", "description": "Google OAuth client secret", "password": true },
    { "type": "promptString", "id": "calendar_refresh_token", "description": "Google OAuth refresh token", "password": true }
  ]
}

Check it with MCP: List Servers.

VS Code MCP documentation

What you can ask it to do

See your schedule

  • What meetings do I have this week? Include the recurring ones.
  • Show tomorrow's 1:1 with its guests, Meet link and reminders.
  • List every occurrence of the team sync in March.

Plan and change meetings

  • Create a 45-minute review on Thursday with two guests and a Google Meet link.
  • Reschedule the retro one hour later and update the guest list — but don't email anyone yet.
  • Move the planning event to the team calendar.
  • Cancel Friday's occurrence of the standup, leaving the rest of the series alone.

Protect your time

  • When are Anna, Boris and I all free for an hour next week?
  • Block Out of Office for my vacation and auto-decline new invitations.
  • Create two hours of Focus Time tomorrow morning and silence Google Chat.

How an event changes

  1. calendar_id: "primary" is your main calendar; other calendars come from list_calendars, and writes need writer access.
  2. A recurring series and a single occurrence have different ids: the series id changes or cancels every occurrence, an instance id (from list_event_instances) exactly one.
  3. update_event changes only the fields you provide, but a nested object replaces its predecessor wholesale — a new attendees list replaces the whole guest list.
  4. No write emails anybody unless send_updates says so — the Calendar API's default is silence.

Out of Office and Focus Time blocks exist only on the primary calendar of a Google Workspace account; consumer Gmail and secondary calendars reject them. Creating an event does not check for conflicts — ask for a free/busy check first. All-day events end on an exclusive date: an event through Friday ends on Saturday's date.

What can change

OperationWhat happensConfirmation boundary
Read calendars, events and free/busyReads schedule data; free/busy shows busy blocks without titlesNo change
Create an eventAdds a timed, all-day or recurring event, optionally with guests and Google MeetChanges a calendar
Create an Out of Office or Focus Time blockAdds a special event that can auto-decline invitations or silence Google ChatChanges a calendar
Update an eventReschedules or edits an event; a series id edits every occurrenceChanges a calendar
Move an eventRe-homes an event to another calendarChanges two calendars
Delete an eventCancels an event or an entire series; there is no undeleteDestructive
Raw API requestCan call API methods without a dedicated toolPotentially destructive

The AI client controls confirmation prompts. The server marks reads, writes and destructive tools so the client can distinguish an inspection from a live change.

Getting access

Access to your own calendars requires OAuth 2.0; an API key is not enough.

  1. Create or select a Google Cloud project and enable Google Calendar API.

  2. Configure the OAuth consent screen and create a Desktop app OAuth client.

  3. Authorize the Google account whose calendars you want to manage. The OAuth 2.0 Playground can obtain the refresh token when Use your own OAuth credentials is enabled.

  4. Request both scopes:

    https://www.googleapis.com/auth/calendar.events
    https://www.googleapis.com/auth/calendar.readonly
    

    The broad https://www.googleapis.com/auth/calendar scope is needed only for raw_request calls that manage calendars or sharing rules themselves.

Testing-mode OAuth refresh tokens can expire after seven days. Publish the OAuth app, or use an Internal app in a Workspace domain, when you need long-lived access. Treat the client secret and refresh token as passwords.

Configuration

VariableRequiredDescription
GOOGLE_CALENDAR_CLIENT_IDYes*OAuth client ID.
GOOGLE_CALENDAR_CLIENT_SECRETYes*OAuth client secret.
GOOGLE_CALENDAR_REFRESH_TOKENYes*OAuth refresh token.
GOOGLE_CALENDAR_ACCESS_TOKENYes*Short-lived (~1 hour) alternative to the OAuth trio.
GOOGLE_CALENDAR_API_BASENoGoogle API base URL override; default https://www.googleapis.com.
GOOGLE_CALENDAR_TIMEOUT_MSNoPer-request timeout; default 60000 ms.
GOOGLE_CALENDAR_MAX_RETRIESNoTemporary-error retries; default 3.

* Provide either the OAuth trio or an access token. Without credentials the server still starts and completes the MCP handshake; the first tool call then names the exact variables to set.

Data, limits and background work

  • Requests go to Google Calendar. The local server refreshes Google OAuth tokens and calls the Calendar API. Its anonymous telemetry contains an installation ID, package version, AI client and platform versions, and tool names — never OAuth tokens, calendar data, tool arguments or prompts. Set ASKADS_TELEMETRY=0 to opt out.
  • Google applies per-project quotas. On 429, the server retries with backoff; reads also retry after network and 5xx errors, while writes are not replayed after an uncertain failure — a duplicated event could re-email every guest.
  • There is no background polling. The server runs only when called. list_events supports incremental checks via updated_min; if your AI app supports scheduled tasks, it can check your calendar periodically.

Technical documentation

Support

Found a bug or need a scenario? Create an issue or write in Telegram.

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