Google Calendar MCP Server

Streamable HTTP MCP server for Google Calendar — manage events, check availability, and schedule meetings.

Author: overment

[!WARNING] You connect this server to your MCP client at your own responsibility. Language models can make mistakes, misinterpret instructions, or perform unintended actions. Review tool outputs, verify changes (e.g., with search_events), and prefer small, incremental writes.

The HTTP/OAuth layer is designed for convenience during development, not production-grade security. If deploying remotely, harden it: proper token validation, secure storage, TLS termination, strict CORS/origin checks, rate limiting, audit logging, and compliance with Google's terms.

Notice

This repo works in two ways:

• As a Node/Hono server for local workflows
• As a Cloudflare Worker for remote interactions

For production Cloudflare deployments, see Remote Model Context Protocol servers (MCP).

Features

• ✅ Events — Search across ALL calendars, create, update, delete, respond to invitations
• ✅ Calendars — Discover available calendars
• ✅ Availability — Check free/busy status before scheduling
• ✅ Natural Language — Create events with text like "Lunch tomorrow at noon"
• ✅ Google Meet — Auto-create Meet links for events
• ✅ OAuth 2.1 — Secure PKCE flow with RS token mapping
• ✅ Dual Runtime — Node.js/Bun or Cloudflare Workers

Design Principles

• LLM-friendly: Tools are simplified and unified, not 1:1 API mirrors
• Smart defaults: Search all calendars, no notification spam, recurring expansion
• Just works: search_events searches all calendars by default — no setup needed
• Clear feedback: Every response includes which calendar each event belongs to
• Limited features: Due to the model's hallucinations, tools for managing calendars are not included. Ensure that you use the client that allows you to confirm dangerous actions, such as event deletion or updating.

Installation

Prerequisites: Bun, Node.js 20+, Google Cloud project. For remote: a Cloudflare account.

Ways to Run (Pick One)

1. Local + OAuth — Standard setup with Google OAuth
2. Cloudflare Worker (wrangler dev) — Local Worker testing
3. Cloudflare Worker (deploy) — Remote production

1. Local + OAuth — Quick Start

1. Set up Google Cloud Console:

   Create Project & Enable API:

   • Go to Google Cloud Console
   • Create a new project (or select existing)
   • Navigate to APIs & Services > Library
   • Search for "Google Calendar API" and click Enable

   Configure OAuth Consent Screen (required before credentials):

   • Go to APIs & Services > OAuth consent screen
   • Select External (or Internal for Workspace)
   • Fill in app name, user support email, developer email
   • Add scopes: ../auth/calendar.events, ../auth/calendar.readonly
   • Add your email as a Test user (required while app is in "Testing" mode)
   • Save

   Create Credentials:

   • Go to APIs & Services > Credentials
   • Click Create Credentials > OAuth client ID
   • Application type: Web application
   • Name: anything (e.g., "Google Calendar MCP")
   • Authorized redirect URIs: http://127.0.0.1:3001/oauth/callback
   • Click Create and copy Client ID and Client Secret

2. Configure environment:

git clone <repo>
cd google-calendar-mcp
bun install
cp env.example .env

Edit .env:

PORT=3000
AUTH_ENABLED=true

PROVIDER_CLIENT_ID=your_client_id
PROVIDER_CLIENT_SECRET=your_client_secret

OAUTH_SCOPES=https://www.googleapis.com/auth/calendar.events https://www.googleapis.com/auth/calendar.readonly
OAUTH_REDIRECT_URI=http://127.0.0.1:3

... [View full README on GitHub](https://github.com/iceener/google-calendar-streamable-mcp-server#readme)