Gmail & PostgreSQL MCP Server

# Quick Start Guide - n8n Integration ## ✅ Your MCP Server is Ready! The server is currently running at: **`http://localhost:3000`** ## 🔌 Connect to n8n in 3 Steps ### Step 1: Open n8n Go to your n8n instance (local or cloud) ### Step 2: Add MCP Client to AI Agent 1. Create a new workflow or open an existing one 2. Add an **AI Agent** node 3. In the AI Agent, add a **Tool** → **MCP Client** 4. Configure the MCP Client with these settings: ``` Endpoint: http://localhost:3000/sse Server Transport: HTTP Streamable Authentication: None Tools to Include: All ``` **Important**: The endpoint must be `http://localhost:3000/sse` (note the `/sse` path!) ### Step 3: Test It! In your AI Agent node, try prompts like: - "List my recent emails" - "Show me all database tables" - "Send an email to test@example.com with subject 'Test' and body 'Hello'" ## 📋 Available Tools Your agent now has access to 8 tools: **Gmail** (4 tools): - `gmail_list_emails` - Search and list emails - `gmail_read_email` - Read email content - `gmail_send_email` - Send emails - `gmail_get_labels` - List all labels **PostgreSQL** (4 tools): - `postgres_query` - Run SELECT queries - `postgres_execute` - Run INSERT/UPDATE/DELETE - `postgres_get_tables` - List all tables - `postgres_get_table_schema` - Get table structure ## 🌐 Deploy to VPS (for Remote Access) If n8n is on a different machine or VPS, you need to deploy the server: ### Quick VPS Deployment 1. **Copy to VPS:** ```bash scp -r dist package.json .env your-user@your-vps:/opt/mcp-server/ ``` 2. **Install on VPS:** ```bash ssh your-user@your-vps cd /opt/mcp-server npm install --production ``` 3. **Update .env:** ```bash nano .env # Change HOST=0.0.0.0 to listen on all interfaces ``` 4. **Open firewall:** ```bash sudo ufw allow 3000/tcp ``` 5. **Run with PM2:** ```bash npm install -g pm2 pm2 start npm --name "mcp-server" -- run start:http pm2 save pm2 startup ``` 6. **In n8n, use:** ``` Endpoint: http://your-vps-ip:3000/sse ``` ## 🔧 Configuration ### Already Configured (.env file): - Gmail API credentials - PostgreSQL connection - Server host and port ### Need to Change Settings? Edit `.env` file: ```bash # For local use HOST=localhost PORT=3000 # For VPS/remote use HOST=0.0.0.0 # Listen on all interfaces PORT=3000 ``` Restart server after changes: ```bash # Kill current server (Ctrl+C if in foreground) npm run start:http ``` ## ✅ Verify Server is Running Test endpoints: ```bash # Health check curl http://localhost:3000/health # Server info (shows all available tools) curl http://localhost:3000/ # Expected response: { "name": "MCP Gmail & PostgreSQL Server", "version": "1.0.0", "transport": "SSE", "endpoints": { "health": "/health", "sse": "/sse", "message": "/message" }, "tools": [...] } ``` ## 🐛 Troubleshooting ### n8n Can't Connect **Check server is running:** ```bash curl http://localhost:3000/health ``` **Check n8n can reach the server:** - If n8n is on same machine: use `http://localhost:3000/sse` - If n8n is remote: use `http://your-server-ip:3000/sse` - Make sure firewall allows port 3000 ### "Gmail service not initialized" Your Gmail credentials in `.env` may be missing or invalid: ```bash # Check .env file has: GMAIL_CLIENT_ID=... GMAIL_CLIENT_SECRET=... GMAIL_REFRESH_TOKEN=... # Generate new refresh token if needed: node scripts/get-gmail-token.js ``` ### "PostgreSQL service not initialized" Your database credentials in `.env` may be incorrect: ```bash # Check .env file has: POSTGRES_HOST=localhost POSTGRES_PORT=5432 POSTGRES_DATABASE=your_db POSTGRES_USER=your_user POSTGRES_PASSWORD=your_password # Test connection: psql -h localhost -U your_user -d your_db ``` ## 📖 Full Documentation - **[N8N_SETUP.md](N8N_SETUP.md)** - Complete n8n integration guide - **[README.md](README.md)** - Full server documentation - **[TESTING.md](TESTING.md)** - Testing guide (if created) ## 🎉 You're All Set! Your MCP server is ready to use with n8n. Start building powerful AI workflows with Gmail and PostgreSQL access! ## Example n8n Workflow Try this simple workflow: 1. **Manual Trigger** → Start workflow 2. **AI Agent** (with your MCP Client configured) → Process request 3. **Set** → Format output In the AI Agent, try: *"List my 5 most recent emails and show me their subjects"* The agent will use the `gmail_list_emails` tool automatically! 🎯