src/
  main.ts                         # Transport bootstrap: stdio or HTTP
  app.module.ts                   # Root Nest module
  config/
    app.config.ts                 # Environment config
  mcp/
    mcp.module.ts                 # MCP Nest module
    mcp.service.ts                # MCP server and request handlers
    http/
      mcp-http.controller.ts      # POST /mcp Streamable HTTP endpoint
    tools/
      base.tool.ts                # Base class for tools
      tool.registry.ts            # Tool list and execution registry
      tools.module.ts             # Nest providers for tools
      ping/
        ping.dto.ts               # Zod schema and output type
        ping.tool.ts              # Example tool implementation

pnpm install

MCP_SERVER_NAME=sample-mcp
MCP_SERVER_VERSION=1.0.0
LOG_LEVEL=log
NODE_ENV=development
TRANSPORT=stdio
PORT=3000

pnpm start

pnpm run start:http

POST http://localhost:3000/mcp

Accept: application/json, text/event-stream
Content-Type: application/json

$body = @{
  jsonrpc = "2.0"
  id = 1
  method = "tools/list"
  params = @{}
} | ConvertTo-Json -Depth 10

Invoke-RestMethod `
  -Method Post `
  -Uri "http://localhost:3000/mcp" `
  -ContentType "application/json" `
  -Headers @{ Accept = "application/json, text/event-stream" } `
  -Body $body

$body = @{
  jsonrpc = "2.0"
  id = 2
  method = "tools/call"
  params = @{
    name = "ping"
    arguments = @{
      message = "hello"
    }
  }
} | ConvertTo-Json -Depth 10

Invoke-RestMethod `
  -Method Post `
  -Uri "http://localhost:3000/mcp" `
  -ContentType "application/json" `
  -Headers @{ Accept = "application/json, text/event-stream" } `
  -Body $body

import { Injectable } from '@nestjs/common';
import type { CallToolResult, Tool } from '@modelcontextprotocol/sdk/types.js';
import { BaseTool } from '../base.tool';

@Injectable()
export class MyTool extends BaseTool {
  get definition(): Tool {
    return {
      name: 'my-tool',
      description: 'Describe what this tool does.',
      inputSchema: {
        type: 'object',
        properties: {
          input: { type: 'string' },
        },
        required: ['input'],
      },
    };
  }

  execute(args: Record<string, unknown>): Promise<CallToolResult> {
    return Promise.resolve(this.success({ args }));
  }
}

pnpm lint
pnpm run lint:fix
pnpm exec tsc --noEmit
pnpm run build