MCP (Model Context Protocol)Complete Guide 2025

# Install MCP SDK
npm install @modelcontextprotocol/sdk

# Install an MCP server (PostgreSQL example)
npm install @modelcontextprotocol/server-postgresql

# Verify installation
npx @modelcontextprotocol/cli --version

// ~/claude_desktop_config.json
{
  "mcpServers": {
    "database": {
      "command": "npx",
      "args": ["@modelcontextprotocol/server-postgresql"],
      "env": {
        "DATABASE_URL": "postgresql://user:password@localhost:5432/mydb"
      }
    },
    "filesystem": {
      "command": "npx",
      "args": ["@modelcontextprotocol/server-filesystem", "/path/to/allowed/directory"]
    },
    "web": {
      "command": "npx",
      "args": ["@modelcontextprotocol/server-web"]
    }
  }
}

import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';

const server = new Server({
  name: 'daznode-mcp-server',
  version: '1.0.0'
});

// Define tools
server.setRequestHandler(ListToolsRequestSchema, async () => ({
  tools: [{
    name: 'get_lightning_stats',
    description: 'Retrieves Lightning Network statistics',
    inputSchema: {
      type: 'object',
      properties: {
        pubkey: { type: 'string', description: 'Node public key' }
      },
      required: ['pubkey']
    }
  }]
}));

// Execute tools
server.setRequestHandler(CallToolRequestSchema, async (request) => {
  if (request.params.name === 'get_lightning_stats') {
    const { pubkey } = request.params.arguments;
    // Logic to retrieve Lightning stats
    return {
      content: [{
        type: 'text',
        text: JSON.stringify(await getLightningStats(pubkey), null, 2)
      }]
    };
  }
});

// Start the server
const transport = new StdioServerTransport();
server.connect(transport);