チャットでサービス連携！MCP実践編 #VSCode – Qiita

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";

// サイコロを振る関数
function rollDice(sides: number): number {
  return Math.floor(Math.random() * sides) + 1;
}

// Create an MCP server
const server = new McpServer({
  name: "DiceRoller",
  version: "1.0.0"
});

// 1. シンプルなサイコロを振るツール
server.tool("rollSimpleDice",
  {
    sides: z.number().describe("サイコロの面数"),
    count: z.number().describe("振るサイコロの個数")
  },
  async ({ sides, count }) => {
    try {
      // サイコロを指定回数振る
      const results: number[] = [];
      for (let i = 0; i  count; i++) {
        results.push(rollDice(sides));
      }

      // 合計値を計算
      const sum = results.reduce((acc, val) => acc + val, 0);

      return {
        content: [{
          type: "text",
          text: `${results.join(", ")}（合計: ${sum}）`
        }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: `エラーが発生しました: ${error.message}` }]
      };
    }
  }
);

// 2. 目標値に対してサイコロを振るツール
server.tool("rollAgainstTarget",
  {
    sides: z.number().describe("サイコロの面数"),
    count: z.number().describe("振るサイコロの個数"),
    target: z.number().describe("成功とみなす最小値")
  },
  async ({ sides, count, target }) => {
    try {
      if (target > sides) {
        return {
          content: [{ type: "text", text: `目標値${target}は${sides}面サイコロでは達成不可能です。` }]
        };
      }

      // サイコロを振る
      const results: number[] = [];
      for (let i = 0; i  count; i++) {
        results.push(rollDice(sides));
      }

      // 判定
      const success = results.some(result => result >= target);
      const resultText = count === 1 ?
        `出目: ${results[0]} → ${success ? "成功" : "失敗"}` :
        `出目: ${results.join(", ")} → ${success ? "成功" : "失敗"}`;

      return {
        content: [{ type: "text", text: resultText }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: `エラーが発生しました: ${error.message}` }]
      };
    }
  }
);

// Start receiving messages on stdin and sending messages on stdout
const transport = new StdioServerTransport();
await server.connect(transport);