NestJS DevTools MCP

Give your AI coding agents (Claude, Cursor, Copilot) the superpower to observe your NestJS application's runtime state in real-time.

Ever wished AI could see your crashed application logs, registered routes, or current DI container without you copy-pasting terminal outputs? This project provides a transparent, near-zero config bridge between your running NestJS app and your AI tools via the Model Context Protocol (MCP).

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Current MCP Tools

Currently available tools:

• discover_servers — Find local NestJS servers with the plugin enabled.
• get_logs — Retrieve recent runtime logs from a detected NestJS server.
• get_routes — List registered HTTP routes (method, path, controller, handler).
• get_request_history — Retrieve recent HTTP request history with filters for method, status, path, duration, and errors.
• get_config — Retrieve sanitized runtime configuration from environment variables and ConfigService.

get_request_history captures real HTTP traffic, including unmatched 404s, without recording request or response bodies by default. Internal /_dev/mcp/* calls are excluded so tool calls do not pollute the history.

get_config is read-only and always masks values that look sensitive, including tokens, passwords, auth keys, private keys, and database URLs. Secret masking cannot be disabled.

More tools may be added in future releases.

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Quick Start (2 Steps)

Step 1: Integrate Plugin into NestJS

Install the plugin package in your NestJS application:

# Using npm
npm install @nestjs-devtools-mcp/plugin

# Using yarn
yarn add @nestjs-devtools-mcp/plugin

# Using pnpm
pnpm add @nestjs-devtools-mcp/plugin

Configure app.module.ts:

import { Module } from '@nestjs/common'
import { DevtoolsMcpModule } from '@nestjs-devtools-mcp/plugin'

@Module({
  imports: [
    DevtoolsMcpModule.register(), // Automatically disables in production
  ],
})
export class AppModule {}

Request body capture is off by default. If you need it for local debugging, enable DevtoolsMcpModule.register({ captureRequestBody: true }); multipart bodies are never captured, and configuration secrets returned by get_config are always masked.

Apply the custom logger in main.ts to allow context interception:

import { NestFactory } from '@nestjs/core'
import { AppModule } from './app.module'
import { applyDevtoolsLogger } from '@nestjs-devtools-mcp/plugin'

async function bootstrap() {
  const app = await NestFactory.create(AppModule, {
    bufferLogs: true,
  })

  // Activate DevTools logger
  applyDevtoolsLogger(app)

  await app.listen(3000)
}
bootstrap()

Step 2: Configure MCP Client

Add the following to your AI Assistant's MCP settings (e.g., claude_desktop_config.json):

{
  "mcpServers": {
    "nestjs-devtools": {
      "command": "npx",
      "args": ["-y", "nestjs-devtools-mcp@latest"]
    }
  }
}

That's it! Restart your MCP client and ask your AI: "Fetch the latest logs from my NestJS application."

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Documentation & Guides

Looking for advanced setups or want to contribute? Dive deeper into our docs:

• Installation & Usage Guide - Advanced setups, installing from source, and troubleshooting.
• Development Guide - For contributors, detailing the monorepo setup, building, testing, and linting.
• API Specs - The MCP protocol specification and contract.

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How it Works (Architecture)

The project uses a secure 2-package model to avoid interfering with your app's logic:

AI Client (Claude, Cursor, ...)
    │
    │  [STDIO - MCP Protocol]
    ▼
nestjs-devtools-mcp (Bridge Server via npx)
    │
    │  [HTTP - Localhost Only]
    ▼
@nestjs-devtools-mcp/plugin (Runs inside your App)
    │
    ▼
NestJS Runtime (Logger, Container, Routes)

1. The Plugin (@nestjs-devtools-mcp/plugin) runs inside your NestJS process, safely collecting runtime data into circular buffers and exposing an internal HTTP endpoint.
2. The Server (nestjs-devtools-mcp) is a lightweight Bridge CLI that manages STDIO communication with the AI and proxies tool calls over HTTP to the plugin.

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License

MIT © HaoNgo232. For production environments, always reassess security assumptions before deploying plugins that observe application state.

Marketplace Ownership Verification

To improve trust signals in LobeHub MCP Marketplace and verify ownership:

1. Keep the MCP badge in this README (already added above).
2. Open your listing page: https://lobehub.com/mcp/hao%20ngo232-nestjs-devtools-mcp.
3. Use the "Check Claim Status" flow and complete GitHub ownership verification.

After LobeHub re-crawls the repository, the owner claim status should be updated on the score page.