Next.js DevTools MCP

Overview

Next.js DevTools MCP is a stdio MCP server for Next.js development workflows. It discovers running Next.js 16+ development servers and proxies the built-in Next.js MCP endpoint at /_next/mcp, provides version-aware local Next.js documentation lookup, and includes browser-evaluation guidance through the agent-browser CLI.

Installation

Install through add-mcp:

npx add-mcp next-devtools-mcp@latest

The add-mcp installer also documents -y to skip prompts/install to detected agents, and -g for global installation. Manual MCP clients can run the server with command npx and args ["-y", "next-devtools-mcp@latest"].

Prerequisites

The upstream README documents Node.js v20.19 or newer LTS, npm or pnpm, and a Next.js 16+ app with a running dev server for the runtime proxy tools. Runtime Next.js MCP tools are discovered from the app server, commonly at http://localhost:3000/_next/mcp.

Configuration

The package uses stdio transport. Runtime environment variables reviewed from README and source:

• NEXT_TELEMETRY_DISABLED: set to 1 to disable anonymous telemetry.
• NEXT_DEVTOOLS_HOST: optional host override for probing Next.js dev servers; defaults to localhost.
• NODE_TLS_REJECT_UNAUTHORIZED: Node TLS setting; when set to 0, source code allows self-signed HTTPS dev-server endpoints. The default safe value is unset.

The README also documents Codex-on-Windows client environment values SystemRoot and PROGRAMFILES; these are client-specific and not included in the generic package transport environment.

Capabilities

• nextjs_index: discovers a running Next.js dev server and lists available Next runtime MCP tools.
• nextjs_call: calls a runtime tool exposed by the Next.js app, such as errors, logs, page metadata, project metadata, and server-action lookup when supported by the app.
• nextjs_docs: retrieves or directs users to version-aware Next.js documentation from the installed Next.js package.
• browser_eval: provides instructions for using the agent-browser CLI for browser automation tasks.

Limitations

The runtime proxy tools require a running Next.js 16+ development server with the Next MCP endpoint available. Auto-discovery can fail on some OS/network combinations, in which case a port may need to be supplied. The browser-evaluation tool does not itself drive a browser; it guides use of agent-browser. The server collects anonymous telemetry by default unless NEXT_TELEMETRY_DISABLED=1 is set, and stores local telemetry/debug files under ~/.next-devtools-mcp. Source review also confirmed the current server exposes tools only, not MCP prompts or resources.