Google Calendar MCP Server

🗓️ Google Calendar MCP Server

This project integrates the Google Calendar v3 APIs with a custom MCP (Model Context Protocol) Server, enabling natural language interaction with your calendar via tools like Claude Desktop.

It acts as a bridge between your calendar data and an LLM using MCP-compatible HTTP streaming.

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🧠 Overview

This project contains two core servers:

1. 🔐 Google OAuth Server

• Handles OAuth 2.0 flow
• Stores and refreshes access tokens in a local session file

2. 🤖 MCP Server

• Implements the Model Context Protocol (MCP)
• Exposes an HTTP streaming interface
• Uses saved credentials to interact with Google Calendar API v3

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🚀 Getting Started

Step 1: 🔧 Set Up Google API Credentials

1. Go to the Google Cloud Console
2. Create or select a project
3. Enable the Google Calendar API
4. Go to Credentials → Create OAuth 2.0 Client ID
   • Choose Desktop App
   • Set branding and add test user emails in audience
5. Download the OAuth credentials as client_secret.json
6. Place this file in the root directory of the project

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Step 2: 📦 Install Dependencies

poetry install

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Step 3: 🚪 Start the OAuth Server

poetry run uvicorn src.main:app --host 0.0.0.0 --port 8000

• This should automatically open a browser for OAuth authentication.
• If not, visit http://0.0.0.0:8000/google_oauth/
• Upon successful authentication, you'll see a success page.
• A session.json file will be created with your access/refresh tokens.

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Step 4: 🧩 Run the MCP Server

poetry run python src/server.py

This launches a streamable MCP-compatible HTTP server at http://localhost:8080/mcp

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Step 5: 🧠 Connect MCP Client (Claude Desktop)

Update the config file at:

~/Library/Application Support/Claude/claude_desktop_config.json

Add the following entry:

{
  "mcpServers": {
    "google-calendar-mcp": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "http://localhost:8080/mcp"
      ]
    }
  }
}

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Step 6: ✅ Verify Integration

• Open Claude Desktop settings.
• If the MCP server was added correctly, it will appear under Settings -> integrations

🧠 Demo

https://github.com/user-attachments/assets/27a8e5ee-8f2f-40c7-bdfc-1caa93767efb

🧱 Project Structure

project-root/
├── client_secret.json         # Google OAuth credentials
├── session.json               # Access/refresh token storage
├── pyproject.toml             # Poetry project config
├── README.md                  

└── src/
    ├── main.py                # FastAPI app for OAuth server
    ├── server.py              # MCP-compatible server
    ├── settings.py            # App settings and constants

    ├── api/
    │   └── oauth_callback.py  # OAuth endpoint logic

    ├── core/
    │   ├── calendar_client.py # Google Calendar API wrapper
    │   ├── mcp_tools.py       # Tools exposed to MCP clients
    │   ├── oauth_manager.py   # OAuth initiation and flow
    │   └── session_manager.py # Token handling

    └── gcalendar_types/       # Typed definitions for Calendar v3 API

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🧩 Dependencies

• FastAPI
• Uvicorn
• Google Auth Libraries
• Poetry for dependency management

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