Google Calendar MCP Server

This MCP server allows Claude to interact with your Google Calendar, enabling capabilities like listing events, creating meetings, and finding free time slots.

Prerequisites

Node.js (v16 or higher)
Claude Desktop App
A Google Cloud Project
Google Calendar API enabled
OAuth 2.0 credentials

Setup Instructions

1. Create a Google Cloud Project

Go to the Google Cloud Console
Create a new project or select an existing one
Enable the Google Calendar API:
- Go to "APIs & Services" > "Library"
- Search for "Google Calendar API"
- Click "Enable"

2. Configure OAuth Consent Screen

Go to "APIs & Services" > "OAuth consent screen"
Select "External" user type (unless you have a Google Workspace organization)
Fill in the required information:
- App name
- User support email
- Developer contact information
Add the following scopes:
- https://www.googleapis.com/auth/calendar
- https://www.googleapis.com/auth/calendar.events
Add your email address as a test user

3. Create OAuth 2.0 Credentials

Go to "APIs & Services" > "Credentials"
Click "Create Credentials" > "OAuth client ID"
Select "Desktop app" as the application type
Name your client (e.g., "MCP Calendar Client")
Click "Create"
Download the client configuration file (you'll need the client ID and client secret)

4. Get Refresh Token

Create a new file named getToken.js:

const { google } = require('googleapis');
const http = require('http');
const url = require('url');

// Replace these with your OAuth 2.0 credentials
const CLIENT_ID = 'your-client-id';
const CLIENT_SECRET = 'your-client-secret';
const REDIRECT_URI = 'http://localhost:3000/oauth2callback';

// Configure OAuth2 client
const oauth2Client = new google.auth.OAuth2(
  CLIENT_ID,
  CLIENT_SECRET,
  REDIRECT_URI
);

// Define scopes
const scopes = [
  'https://www.googleapis.com/auth/calendar',
  'https://www.googleapis.com/auth/calendar.events'
];

async function getRefreshToken() {
  return new Promise((resolve, reject) => {
    try {
      // Create server to handle OAuth callback
      const server = http.createServer(async (req, res) => {
        try {
          const queryParams = url.parse(req.url, true).query;
          
          if (queryParams.code) {
            // Get tokens from code
            const { tokens } = await oauth2Client.getToken(queryParams.code);
            console.log('\n=================');
            console.log('Refresh Token:', tokens.refresh_token);
            console.log('=================\n');
            console.log('Save this refresh token in your configuration!');
            
            // Send success response
            res.end('Authentication successful! You can close this window.');
            
            // Close server
            server.close();
            resolve(tokens);
          }
        } catch (error) {
          console.error('Error getting tokens:', error);
          res.end('Authentication failed! Please check console for errors.');
          reject(error);
        }
      }).listen(3000, () => {
        // Generate auth url
        const authUrl = oauth2Client.generateAuthUrl({
          access_type: 'offline',
          scope: scopes,
          prompt: 'consent'  // Force consent screen to ensure refresh token
        });

        console.log('1. Copy this URL and paste it in your browser:');
        console.log('\n', authUrl, '\n');
        console.log('2. Follow the Google authentication process');
        console.log('3. Wait for the refresh token to appear here');
      });

    } catch (error) {
      console.error('Server creation error:', error);
      reject(error);
    }
  });
}

// Run the token retrieval
getRefreshToken().catch(console.error);

Install required dependency:

npm install googleapis

Update the script with your OAuth credentials:
- Replace your-client-id with your actual client ID
- Replace your-client-secret with your actual client secret
Run the script:

node getToken.js

Follow the instructions in the console:
- Copy the provided URL
- Paste it into your browser
- Complete the Google authentication process
- Copy the refresh token that appears in the console

5. Configure Claude Desktop

Open your Claude Desktop configuration file:

For MacOS:

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

For Windows:

code %AppData%\Claude\claude_desktop_config.json

Add or update the configuration:

{
    "mcpServers": {
        "google-calendar": {
            "command": "node",
            "args": [
                "/ABSOLUTE/PATH/TO/YOUR/build/index.js"
            ],
            "env": {
                "GOOGLE_CLIENT_ID": "your_client_id_here",
                "GOOGLE_CLIENT_SECRET": "your_client_secret_here",
                "GOOGLE_REDIRECT_URI": "http://localhost",
                "GOOGLE_REFRESH_TOKEN": "your_refresh_token_here"
            }
        }
    }
}

Save the file and restart Claude Desktop

Initial Project Setup

Create a new directory for your project:

mkdir google-calendar-mcp
cd google-calendar-mcp

Initialize a new npm project:

npm init -y

Install dependencies:

npm install @modelcontextprotocol/sdk googleapis google-auth-library zod
npm install -D @types/node typescript

Create a tsconfig.json file:

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "Node16",
    "moduleResolution": "Node16",
    "outDir": "./build",
    "rootDir": "./src",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}

Update package.json:

{
  "type": "module",
  "scripts": {
    "build": "tsc && node -e \"require('fs').chmodSync('build/index.js', '755')\""
  }
}

Create your source directory:

mkdir src

Create a .env file for local development (don't commit this file):

GOOGLE_CLIENT_ID=your_client_id_here
GOOGLE_CLIENT_SECRET=your_client_secret_here
GOOGLE_REDIRECT_URI=http://localhost
GOOGLE_REFRESH_TOKEN=your_refresh_token_here

Building and Running

Build the server:

npm run build

The server will automatically start when you open Claude Desktop

Available Tools

The server provides the following tools:

list_events: List calendar events within a specified time range
create_event: Create a new calendar event
update_event: Update an existing calendar event
delete_event: Delete a calendar event
find_free_time: Find available time slots in the calendar

Example Usage in Claude

After setup, you can use commands like:

"Show me my calendar events for next week"
"Schedule a meeting with [email_id] tomorrow at 2 PM for 1 hour"
"Find a free 30-minute slot this afternoon"
"Update my 3 PM meeting to 4 PM"
"Cancel my meeting with ID [event_id]"

Troubleshooting

Common Issues

Tools not appearing in Claude:
- Check Claude Desktop logs: tail -f ~/Library/Logs/Claude/mcp*.log
- Verify all environment variables are set correctly
- Ensure the path to index.js is absolute and correct
Authentication Errors:
- Verify your OAuth credentials are correct
- Check if refresh token is valid
- Ensure required scopes are enabled
Server Connection Issues:
- Check if the server built successfully
- Verify file permissions on build/index.js (should be 755)
- Try running the server directly: node /path/to/build/index.js

Viewing Logs

To view server logs:

# For MacOS/Linux:
tail -n 20 -f ~/Library/Logs/Claude/mcp*.log

# For Windows:
Get-Content -Path "$env:AppData\Claude\Logs\mcp*.log" -Wait -Tail 20

Environment Variables

If you're getting environment variable errors, verify each one:

GOOGLE_CLIENT_ID: Should start with something like "123456789-..."
GOOGLE_CLIENT_SECRET: Usually ends in ".apps.googleusercontent.com"
GOOGLE_REDIRECT_URI: Should be "http://localhost"
GOOGLE_REFRESH_TOKEN: A long string that doesn't expire

Security Considerations

Keep your OAuth credentials secure
Don't commit credentials to version control
Use environment variables for sensitive data
Regularly rotate refresh tokens
Monitor API usage in Google Cloud Console

License

MIT License - See LICENSE file for details.

Support

If you encounter any issues:

Check the troubleshooting section above
Review Claude Desktop logs
Open an issue on GitHub
Contact the maintainer

Features

Rate this server

Features

Rate this server