Enabling MCP Server in Next.js – Real-Time Agent Access to Your App’s Internal Structure

Introduction

The Model Context Protocol (MCP) is an open standard that enables coding agents to interact with your application through a unified interface. Next.js 16+ includes built-in MCP support, allowing agents to access runtime data, page metadata, and development logs in real time.

Getting Started

Requirements: Next.js version 16 or higher

Create a .mcp.json file in the root of your project and add:

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

Once you run npm run dev, next-devtools-mcp will automatically connect to your running Next.js instance.

Capabilities

next-devtools-mcp provides agents with access to:

Build, runtime, and type errors
Live application state and runtime info
Page routes, components, and rendering metadata
Server Actions and component hierarchies
Development logs and console output

Development Tools

Next.js documentation and best practices
Migration helpers and codemods for upgrading to Next.js 16
Cache Components setup guidance
Playwright MCP integration for browser testing

Workflow

Run npm run dev
Your agent connects automatically via MCP
Open your app in the browser
Query your agent for diagnostics and insights

Available Tools

get_errors: Retrieve current errors
get_logs: Access development logs
get_page_metadata: Get page structure and rendering info
get_project_metadata: View project config and dev server URL
get_server_action_by_id: Locate Server Actions by ID

Benefits of Agent-Assisted Development

Context-aware feature suggestions
Live state and route inspection
Understanding of App Router layout
Code generation aligned with project conventions

Examples

Error Diagnosis

Ask: “What errors are currently in my application?”

The agent will query your dev server, retrieve errors, and suggest fixes.

Upgrading and Conceptual Help

Ask: “Help me upgrade to Next.js 16”

The agent will analyze your setup, run codemods, and guide you through breaking changes.

Conceptual Questions

Ask: “When should I use 'use client' in App Router?”

The agent will query the Next.js knowledge base and provide documentation-backed answers.

How It Works

Next.js 16+ exposes an MCP endpoint at /_next/mcp. The next-devtools-mcp package discovers and connects to this endpoint, enabling:

Multi-instance support across ports
Tool call forwarding
A unified interface for agents

Troubleshooting

Ensure you're using Next.js v16+
Verify .mcp.json is configured
Restart your dev server if needed
Confirm your agent has loaded the MCP configuration

Conclusion

By enabling MCP in Next.js, you unlock powerful agent-assisted development features. From real-time diagnostics to intelligent code generation, MCP transforms your workflow into a faster, smarter experience.