NestJS MCP模块

一个用于实现Model Context Protocol服务器的NestJS模块,支持实时通信和工具执行的Server-Sent Events (SSE)。

  • by omnihash
  • TypeScript
  • 本地部署
  • 2 星标
  • 更新于
在 GitHub 查看 omnihash/nestjs-mcp

使用说明

用于实现模型上下文协议服务器的NestJS模块。该模块将MCP协议稳健地集成到NestJS应用程序中,支持服务器发送事件(SSE)进行实时通信和工具执行。

特性

  • 🔄 服务器发送事件(SSE)支持
  • 🛠️ 工具注册和执行
  • 📝 JSON-RPC消息格式
  • ❤️ 心跳机制
  • ✅ Zod模式验证
  • 🚀 与NestJS轻松集成

安装

yarn add @omnihash/nestjs-mcp
# or
npm install @omnihash/nestjs-mcp

用法

1.导入模块

有三种方法可以使用MCP模块:使用装饰器、手动注册或两者兼而有之。

使用装饰品(推荐)

首先,使用装饰器创建工具服务:

// math-tools.service.ts
import { Injectable } from '@nestjs/common';
import { z } from 'zod';
import { McpTool, McpTools } from '@omnihash/nestjs-mcp';

@Injectable()
@McpTools('math')
export class MathToolsService {
  @McpTool({
    name: 'add',
    description: 'Add two numbers',
    schema: z.object({
      a: z.number().describe('First number'),
      b: z.number().describe('Second number'),
    }),
  })
  async add({ a, b }: { a: number; b: number }): Promise<number> {
    return a + b;
  }

  @McpTool({
    name: 'multiply',
    description: 'Multiply two numbers',
    schema: z.object({
      a: z.number().describe('First number'),
      b: z.number().describe('Second number'),
    }),
  })
  async multiply({ a, b }: { a: number; b: number }): Promise<number> {
    return a * b;
  }

  @McpTool({
    name: 'divide',
    description: 'Divide two numbers',
    schema: z.object({
      dividend: z.number().describe('The dividend'),
      divisor: z.number().describe('The divisor'),
    }),
  })
  async divide({
    dividend,
    divisor,
  }: {
    dividend: number;
    divisor: number;
  }): Promise<number> {
    if (divisor === 0) {
      throw new Error('Division by zero is not allowed');
    }
    return dividend / divisor;
  }

  @McpTool({
    name: 'sqrt',
    description: 'Calculate square root',
    schema: z.object({
      n: z.number().min(0).describe('Number to find square root of'),
    }),
  })
  async sqrt({ n }: { n: number }): Promise<number> {
    return Math.sqrt(n);
  }

  @McpTool({
    name: 'power',
    description: 'Calculate power',
    schema: z.object({
      base: z.number().describe('Base number'),
      exponent: z.number().describe('Exponent'),
    }),
  })
  async power({
    base,
    exponent,
  }: {
    base: number;
    exponent: number;
  }): Promise<number> {
    return Math.pow(base, exponent);
  }
}

// string-tools.service.ts
@Injectable()
@McpTools('string')
export class StringToolsService {
  @McpTool({
    name: 'reverse',
    description: 'Reverse a string',
    schema: z.object({
      text: z.string().describe('Text to reverse'),
    }),
  })
  async reverse({ text }: { text: string }): Promise<string> {
    return text.split('').reverse().join('');
  }

  @McpTool({
    name: 'wordCount',
    description: 'Count words in text',
    schema: z.object({
      text: z.string().describe('Text to count words in'),
      includeNumbers: z
        .boolean()
        .default(false)
        .describe('Include numbers in word count'),
    }),
  })
  async wordCount({
    text,
    includeNumbers,
  }: {
    text: string;
    includeNumbers: boolean;
  }): Promise<{
    totalWords: number;
    uniqueWords: number;
    wordFrequency: Record<string, number>;
  }> {
    const words = text.toLowerCase().match(/\b\w+\b/g) || [];
    const filteredWords = includeNumbers
      ? words
      : words.filter((word) => isNaN(Number(word)));

    const frequency: Record<string, number> = {};
    filteredWords.forEach((word) => {
      frequency[word] = (frequency[word] || 0) + 1;
    });

    return {
      totalWords: filteredWords.length,
      uniqueWords: Object.keys(frequency).length,
      wordFrequency: frequency,
    };
  }

  @McpTool({
    name: 'capitalize',
    description: 'Capitalize first letter of each word',
    schema: z.object({
      text: z.string().describe('Text to capitalize'),
    }),
  })
  async capitalize({ text }: { text: string }): Promise<string> {
    return text.replace(/\b\w/g, (char) => char.toUpperCase());
  }

  @McpTool({
    name: 'extractEmails',
    description: 'Extract all email addresses from text',
    schema: z.object({
      text: z.string().describe('Text to search for emails'),
    }),
  })
  async extractEmails({ text }: { text: string }): Promise<string[]> {
    const emailRegex = /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g;
    return text.match(emailRegex) || [];
  }
}

// Create a module to provide your tools
@Module({
  providers: [MathToolsService, StringToolsService],
  exports: [MathToolsService, StringToolsService],
})
export class ToolsModule {}

然后在你的 app.module.ts:

import { Module } from '@nestjs/common';
import { McpModule } from '@omnihash/nestjs-mcp';
import { ToolsModule } from './tools/tools.module';

@Module({
  imports: [
    McpModule.forRoot({
      name: 'my-mcp-server',
      version: '1.0.0',
      description: 'My MCP Server Implementation',
    }),
    ToolsModule,
  ],
})
export class AppModule {}

手动注册

或者,您可以手动注册工具:

import { Module } from '@nestjs/common';
import { McpModule } from '@omnihash/nestjs-mcp';
import { z } from 'zod';

@Module({
  imports: [
    McpModule.forRootAsync({
      useFactory: () => ({
        name: 'my-mcp-server',
        version: '1.0.0',
        description: 'MCP server with manual tools',
        tools: [
          {
            name: 'greet',
            schema: z.object({
              name: z.string().describe('Name to greet'),
            }),
            handler: async ({ name }) => {
              return `Hello, ${name}!`;
            },
          },
        ],
      }),
    }),
    // Note: You can also register decorator tools alongside your
    // manual registration by importing your ToolsModule
    ToolsModule,
  ],
})
export class AppModule {}

可用端点

导入模块后,以下端点将可用:

  • GET /sse -建立SSE连接
  • POST /messages -处理MCP消息
  • GET /health -健康检查端点
  • GET /capabilities -返回服务器功能

配置选项

这 McpModule.forRoot() 方法接受以下选项:

interface McpModuleOptions {
  name: string; // Server name
  version: string; // Server version
  description: string; // Server description
  tools: McpTool[]; // Array of tools
}

interface McpTool {
  name: string; // Tool name
  schema: z.ZodObject; // Zod schema for input validation
  handler: (params: any) => Promise<any>; // Tool implementation
}

许可证

麻省理工学院

更多示例

项目结构示例

src/
  ├── app.module.ts           # Example application module
  ├── main.ts                # Application entry point
  └── tools/                 # Example tool implementations
      ├── api-tools.service.ts
      ├── math-tools.service.ts
      ├── string-tools.service.ts
      └── tools.module.ts

API工具

// api-tools.service.ts
import { Injectable } from '@nestjs/common';
import axios from 'axios';
import { z } from 'zod';
import { McpTool, McpTools } from '@omnihash/nestjs-mcp';

@Injectable()
@McpTools('api')
export class ApiToolsService {
  @McpTool({
    name: 'getTodoList',
    description: 'Get a todo item by ID',
    schema: z.object({
      id: z.string().describe('Todo list ID'),
    }),
  })
  async getTodoList({ id }: { id: string }): Promise<any> {
    const response = await axios.get(
      `https://jsonplaceholder.typicode.com/todos/${id}`,
    );
    return response.data;
  }
}

数学工具(扩展)

@McpTool({
  name: 'divide',
  description: 'Divide two numbers',
  schema: z.object({
    dividend: z.number().describe('The dividend'),
    divisor: z.number().describe('The divisor'),
  }),
})
async divide({
  dividend,
  divisor,
}: {
  dividend: number;
  divisor: number;
}): Promise<number> {
  if (divisor === 0) {
    throw new Error('Division by zero is not allowed');
  }
  return dividend / divisor;
}

@McpTool({
  name: 'sqrt',
  description: 'Calculate square root',
  schema: z.object({
    n: z.number().min(0).describe('Number to find square root of'),
  }),
})
async sqrt({ n }: { n: number }): Promise<number> {
  return Math.sqrt(n);
}

@McpTool({
  name: 'power',
  description: 'Calculate power',
  schema: z.object({
    base: z.number().describe('Base number'),
    exponent: z.number().describe('Exponent'),
  }),
})
async power({
  base,
  exponent,
}: {
  base: number;
  exponent: number;
}): Promise<number> {
  return Math.pow(base, exponent);
}

字符串工具(扩展)

@McpTool({
  name: 'capitalize',
  description: 'Capitalize first letter of each word',
  schema: z.object({
    text: z.string().describe('Text to capitalize'),
  }),
})
async capitalize({ text }: { text: string }): Promise<string> {
  return text.replace(/\b\w/g, (char) => char.toUpperCase());
}

@McpTool({
  name: 'extractEmails',
  description: 'Extract all email addresses from text',
  schema: z.object({
    text: z.string().describe('Text to search for emails'),
  }),
})
async extractEmails({ text }: { text: string }): Promise<string[]> {
  const emailRegex = /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g;
  return text.match(emailRegex) || [];
}

高级用法

工具发现

该模块自动发现装饰有 @McpTool 在服务装饰 @McpTools。这意味着您可以将工具组织成逻辑组:

@Injectable()
@McpTools('math')      // Tools will be prefixed with 'math/'
export class MathTools {
  @McpTool({
    name: 'add',       // Will be available as 'math/add'
    description: '...',
    schema: z.object({...}),
  })
  async add() {...}
}

@Injectable()
@McpTools('string')    // Tools will be prefixed with 'string/'
export class StringTools {
  @McpTool({
    name: 'reverse',   // Will be available as 'string/reverse'
    description: '...',
    schema: z.object({...}),
  })
  async reverse() {...}
}

错误处理

工具可能会抛出错误,这些错误将在MCP响应中正确格式化:

@McpTool({
  name: 'divide',
  schema: z.object({
    dividend: z.number(),
    divisor: z.number(),
  }),
})
async divide({ dividend, divisor }) {
  if (divisor === 0) {
    throw new Error('Division by zero');  // Will be returned as a JSON-RPC error
  }
  return dividend / divisor;
}

异步配置

您可以使用 forRootAsync 对于动态配置:

@Module({
  imports: [
    McpModule.forRootAsync({
      imports: [ConfigModule],
      inject: [ConfigService],
      useFactory: (config: ConfigService) => ({
        name: config.get('MCP_SERVER_NAME'),
        version: config.get('MCP_SERVER_VERSION'),
        description: config.get('MCP_SERVER_DESCRIPTION'),
      }),
    }),
  ],
})
export class AppModule {}

自定义工具响应类型

工具可以返回复杂的对象,这些对象将自动转换为MCP内容:

@McpTool({
  name: 'analyze',
  schema: z.object({
    text: z.string(),
  }),
})
async analyze({ text }) {
  return {
    wordCount: text.split(/\s+/).length,
    charCount: text.length,
    sentiment: calculateSentiment(text),
    language: detectLanguage(text),
  };
}

发展

先决条件

  • Node.js 18或更高版本
  • npm或纱线

设置

  1. 克隆存储库
git clone git@github.com:omnihash/nestjs-mcp.git
cd nestjs-mcp
  1. 安装依赖项
nvm use
yarn install
  1. 运行示例服务器
yarn start:dev

运行测试

# Unit tests
yarn test

# E2E tests
yarn test:e2e

# Test coverage
yarn test:cov

贡献

  1. 分叉存储库
  2. 创建功能分支(git checkout -b feature/amazing-feature)
  3. 提交您的更改(git commit -m 'Add some amazing feature')
  4. 推到分支(git push origin feature/amazing-feature)
  5. 打开拉取请求

地方发展

要在另一个项目中本地开发和测试该模块:

  1. 链接包:
cd nestjs-mcp
npm link
  1. 在您的项目中:
cd your-project
npm link @omnihash/nestjs-mcp
  1. 添加到您的项目 package.json:
{
  "dependencies": {
    "@omnihash/nestjs-mcp": "*"
  }
}