mcp-development

MCP Development

What is MCP?

The Model Context Protocol (MCP) is an open protocol that enables AI assistants to interact with external tools, data sources, and services in a standardized way.

Core Concepts

MCP Server Structure

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

const server = new Server({
  name: "my-mcp-server",
  version: "1.0.0",
}, {
  capabilities: {
    tools: {},
    resources: {},
  }
});

// Define tools
server.setRequestHandler("tools/list", async () => ({
  tools: [
    {
      name: "get_data",
      description: "Fetch data from the API",
      inputSchema: {
        type: "object",
        properties: {
          id: { type: "string", description: "Item ID" }
        },
        required: ["id"]
      }
    }
  ]
}));

// Handle tool calls
server.setRequestHandler("tools/call", async (request) => {
  const { name, arguments: args } = request.params;
  
  if (name === "get_data") {
    const result = await fetchData(args.id);
    return { content: [{ type: "text", text: JSON.stringify(result) }] };
  }
  
  throw new Error(`Unknown tool: ${name}`);
});

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

Tool Design Best Practices

Clear Descriptions

{
  name: "search_documents",
  description: "Search documents by keyword. Returns matching documents with relevance scores. Use when the user asks to find or search for specific content.",
  inputSchema: {
    type: "object",
    properties: {
      query: {
        type: "string",
        description: "Search query - can include multiple keywords"
      },
      limit: {
        type: "integer",
        description: "Maximum number of results (default: 10)",
        default: 10
      }
    },
    required: ["query"]
  }
}