MCP Lottery Demo

Instructions

Implementation Reference

• src/server.js:218-253 (handler)

  Handler for flip_coin tool in stdio MCP server switch statement: validates input count, performs multiple coin flips using Math.random() < 0.5 for '正面'(heads) or '反面'(tails), tallies results, formats output text.

  case 'flip_coin': {
    // 抛硬币工具：模拟抛硬币
    const { count = 1 } = args;
    
    // 参数验证
    if (count < 1) {
      throw new Error('抛硬币次数至少为1');
    }
  
    // 执行抛硬币逻辑
    const results = [];
    let heads = 0;  // 正面次数
    let tails = 0;  // 反面次数
    
    for (let i = 0; i < count; i++) {
      // 50% 概率生成正面或反面
      const result = Math.random() < 0.5 ? '正面' : '反面';
      results.push(result);
      if (result === '正面') heads++;
      else tails++;
    }
  
    // 根据抛硬币次数格式化输出
    const resultText = count === 1 
      ? `🪙 抛硬币结果：${results[0]}`
      : `🪙 抛硬币结果：${results.join(', ')}\n📊 统计：正面 ${heads} 次，反面 ${tails} 次`;
  
    return {
      content: [
        {
          type: 'text',
          text: resultText,
        },
      ],
    };
  }

• src/server-http.js:143-173 (handler)

  Handler for flip_coin tool in HTTP server's handleToolCall function: identical implementation to stdio server version.

  case 'flip_coin': {
    const { count = 1 } = args;
    
    if (count < 1) {
      throw new Error('抛硬币次数至少为1');
    }
  
    const results = [];
    let heads = 0;
    let tails = 0;
    
    for (let i = 0; i < count; i++) {
      const result = Math.random() < 0.5 ? '正面' : '反面';
      results.push(result);
      if (result === '正面') heads++;
      else tails++;
    }
  
    const resultText = count === 1 
      ? `🪙 抛硬币结果：${results[0]}`
      : `🪙 抛硬币结果：${results.join(', ')}\n📊 统计：正面 ${heads} 次，反面 ${tails} 次`;
  
    return {
      content: [
        {
          type: 'text',
          text: resultText,
        },
      ],
    };
  }

• src/server.js:98-110 (registration)

  Registration of flip_coin tool in tools array for ListToolsRequestHandler, including name, description, and input schema.

    name: 'flip_coin',
    description: '抛硬币，返回正面或反面',
    inputSchema: {
      type: 'object',
      properties: {
        count: {
          type: 'number',
          description: '抛硬币次数，默认为1',
          default: 1,
        },
      },
    },
  },

• src/server-http.js:55-67 (registration)

  Registration of flip_coin tool in tools array for HTTP /tools endpoint, including name, description, and input schema.

    name: 'flip_coin',
    description: '抛硬币，返回正面或反面',
    inputSchema: {
      type: 'object',
      properties: {
        count: {
          type: 'number',
          description: '抛硬币次数，默认为1',
          default: 1,
        },
      },
    },
  },