MCPサーバを自作してClaude Codeにつなぐ — TypeScript実装の完全手順

mkdir my-mcp-server && cd my-mcp-server
npm init -y
npm install @modelcontextprotocol/sdk zod
npm install -D typescript @types/node tsx
npx tsc --init

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "Node16",
    "moduleResolution": "Node16",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "outDir": "dist"
  },
  "include": ["src/**/*"]
}

import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
  CallToolRequestSchema,
  ListToolsRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
 
const server = new Server(
  {
    name: "my-mcp-server",
    version: "0.1.0",
  },
  {
    capabilities: {
      tools: {},
    },
  },
);
 
// ツール一覧の応答
server.setRequestHandler(ListToolsRequestSchema, async () => ({
  tools: [
    {
      name: "echo",
      description: "入力をそのまま返す動作確認用ツール",
      inputSchema: {
        type: "object",
        properties: {
          message: {
            type: "string",
            description: "返却したい文字列",
          },
        },
        required: ["message"],
      },
    },
  ],
}));
 
// ツール呼び出しの処理
server.setRequestHandler(CallToolRequestSchema, async (request) => {
  if (request.params.name === "echo") {
    const message = request.params.arguments?.message ?? "";
    return {
      content: [
        {
          type: "text",
          text: `Echo: ${message}`,
        },
      ],
    };
  }
  throw new Error(`Unknown tool: ${request.params.name}`);
});
 
// stdio で起動
const transport = new StdioServerTransport();
await server.connect(transport);

{
  "mcpServers": {
    "my-mcp": {
      "command": "npx",
      "args": ["--yes", "tsx", "/absolute/path/to/my-mcp-server/src/server.ts"]
    }
  }
}

@my-mcp echo こんにちは

import { glob } from "node:fs/promises";
import { readFile } from "node:fs/promises";
import path from "node:path";
 
// ListToolsRequestSchema の handler に追加
{
  name: "search-files",
  description: "指定ディレクトリ内でファイルを glob 検索し、本文の先頭を返す",
  inputSchema: {
    type: "object",
    properties: {
      pattern: { type: "string", description: "glob パターン(例: '**/*.ts')" },
      cwd: { type: "string", description: "検索起点ディレクトリ" },
      limit: { type: "number", description: "返却ファイル数の上限", default: 10 },
    },
    required: ["pattern", "cwd"],
  },
}
 
// CallToolRequestSchema の handler に追加
if (request.params.name === "search-files") {
  const { pattern, cwd, limit = 10 } = request.params.arguments as {
    pattern: string;
    cwd: string;
    limit?: number;
  };
  
  // 安全のため、cwd 外への参照を遮断
  const resolved = path.resolve(cwd);
  
  const files: string[] = [];
  for await (const file of glob(pattern, { cwd: resolved })) {
    files.push(file);
    if (files.length >= limit) break;
  }
  
  const results = await Promise.all(
    files.map(async (f) => {
      const full = path.join(resolved, f);
      const head = (await readFile(full, "utf-8")).slice(0, 500);
      return `## ${f}\n${head}\n...`;
    }),
  );
  
  return {
    content: [
      {
        type: "text",
        text: results.join("\n\n") || "(該当ファイルなし)",
      },
    ],
  };
}

import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
import express from "express";
 
// ... server の定義は同じ
 
const app = express();
 
// SSE エンドポイント
app.get("/sse", async (req, res) => {
  const transport = new SSEServerTransport("/messages", res);
  await server.connect(transport);
});
 
// メッセージ受信エンドポイント
app.post("/messages", express.json(), async (req, res) => {
  // transport がここで POST を捌く
});
 
app.listen(3000, () => {
  console.log("MCP server on http://localhost:3000");
});

{
  "mcpServers": {
    "my-mcp": {
      "url": "http://localhost:3000/sse"
    }
  }
}

app.use((req, res, next) => {
  if (req.path === "/sse" || req.path === "/messages") {
    const auth = req.headers.authorization;
    if (auth !== `Bearer ${process.env.MCP_TOKEN}`) {
      res.status(401).send("Unauthorized");
      return;
    }
  }
  next();
});

{
  "mcpServers": {
    "my-mcp": {
      "url": "https://my-mcp.example.com/sse",
      "headers": {
        "Authorization": "Bearer ${MCP_TOKEN}"
      }
    }
  }
}