NestJS MCP

Add the NestJS MCP wrapper, the official MCP SDK, and Zod (used for parameter schema validation) to your NestJS project.

npm install @nestjs-mcp/server @modelcontextprotocol/sdk zod

Register McpModule.forRoot() (or forRootAsync() for environment-based config) in your root module. Provide at minimum a server name and version; all other options have sensible defaults including 30-minute session timeouts and up to 1000 concurrent sessions.

import { McpModule } from '@nestjs-mcp/server';

@Module({
  imports: [
    McpModule.forRoot({
      name: 'my-mcp-server',
      version: '1.0.0',
      instructions: 'Tools for interacting with My Service API'
    })
  ]
})
export class AppModule {}

Define a Resolver class and annotate methods with @Tool(), @Resource(), or @Prompt(). The library auto-discovers all Resolvers in the NestJS provider graph — no manual registration is needed. Methods receive the tool parameters as their first argument and a RequestHandlerExtra object as the last.

import { Resolver, Tool } from '@nestjs-mcp/server';
import { z } from 'zod';

@Resolver('calculator')
export class CalculatorResolver {
  @Tool({ name: 'add_numbers', description: 'Add two numbers together' })
  add(params: { a: number; b: number }) {
    return { content: [{ type: 'text', text: String(params.a + params.b) }] };
  }
}

Add your Resolver to the providers array of the appropriate NestJS module so the dependency injection container can find it.

@Module({
  imports: [McpModule.forRoot({ name: 'my-mcp-server', version: '1.0.0' })],
  providers: [CalculatorResolver]
})
export class AppModule {}

Run your NestJS app normally with 'npm run start'. The MCP endpoints are served alongside your existing HTTP routes. Point your MCP client at the server's Streamable HTTP or SSE endpoint (e.g., http://localhost:3000/mcp).

npm run start