Next.js DevTools MCP

`next-devtools-mcp` is a Model Context Protocol (MCP) server that connects coding agents like Claude and Cursor to your running Next.js dev server.

It is a thin connector. It discovers running Next.js 16+ dev servers and proxies their built-in MCP endpoint (`/_next/mcp`) so agents get live runtime errors, routes, and logs. It also ships two gateways that point agents at tools they run directly: version-accurate docs and the `agent-browser` CLI.

> [!NOTE]

> Docs and migration workflows no longer live in this server. Next.js bundles its own docs at `node_modules/next/dist/docs/`, and upgrade / Cache Components workflows are distributed as agent skills. See Migrating from 0.3.x.

Requirements

• Node.js v20.19 or a newer LTS version
• npm or pnpm
• Next.js 16+ with a running dev server (for `nextjs_index` / `nextjs_call`)

Install

Install for all your coding agents with `add-mcp`:

npx add-mcp next-devtools-mcp@latest

Add `-y` to skip the prompt and install to all detected agents. Add `-g` to install globally across all projects.

Or add the config to your MCP client manually:

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

> [!NOTE]

> `next-devtools-mcp@latest` keeps your client on the latest version.

Client-specific setup

Amp

amp mcp add next-devtools -- npx next-devtools-mcp@latest

Or follow Amp's MCP docs with the config above.

Claude Code

claude mcp add next-devtools npx next-devtools-mcp@latest

Or edit your MCP settings file with the config above.

Codex

codex mcp add next-devtools -- npx next-devtools-mcp@latest

Windows 11: add environment variables and a longer startup timeout to `.codex/config.toml`:

env = { SystemRoot="C:\\Windows", PROGRAMFILES="C:\\Program Files" }
startup_timeout_ms = 20_000

Cursor

Install in Cursor

Or go to `Cursor Settings` → `MCP` → `New MCP Server` and use the config above.

Gemini

# Project
gemini mcp add next-devtools npx next-devtools-mcp@latest

# Global
gemini mcp add -s user next-devtools npx next-devtools-mcp@latest

Google Antigravity

Add to `.gemini/antigravity/mcp_config.json`:

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

See the Antigravity MCP docs.

VS Code / Copilot

code --add-mcp '{"name":"next-devtools","command":"npx","args":["-y","next-devtools-mcp@latest"]}'

Or follow the official VS Code MCP setup guide.

Warp

`Settings | AI | Manage MCP Servers` → `+ Add`:

• Name: `next-devtools`
• Command: `npx`
• Arguments: `-y, next-devtools-mcp@latest`

Quick Start

Start your Next.js dev server:

npm run dev

Next.js 16+ enables its MCP endpoint by default at `http://localhost:3000/_next/mcp`. `next-devtools-mcp` discovers and connects to it automatically — no config needed.

Then ask your agent about the running app:

Next Devtools, what errors are in my Next.js application?
Next Devtools, show me the structure of my routes
Next Devtools, what's in the development server logs?

The agent calls `nextjs_index` to discover servers, then `nextjs_call` to query their real state.

Tools

The gateways do not do the work themselves — they tell the agent where the docs are or how to install/run the CLI, and the agent runs it directly (faster than proxying through MCP).

nextjs_index — discover servers

Scans common ports for running Next.js 16+ dev servers and lists each server's built-in runtime tools at `/_next/mcp`. No parameters.

Runtime tools exposed by Next.js (varies by version):

• `get_errors` — current build, runtime, and type errors
• `get_logs` — path to the dev log file (browser console + server output)
• `get_page_metadata` — routes, pages, component metadata
• `get_project_metadata` — project structure, config, dev server URL
• `get_server_action_by_id` — resolve a Server Action ID to its source file

Output: JSON listing discovered servers (port, PID, URL) and their tools.

nextjs_call — run a runtime tool

Calls one runtime tool on a discovered server. Run `nextjs_index` first to find the port and tool name.

Input:

• `port` (required) — dev server port
• `toolName` (required) — runtime tool to invoke
• `args` (optional) — arguments object, only if the tool requires them

{ "port": 3000, "toolName": "get_errors" }

Output: JSON with the tool's result.

nextjs_docs — find version-accurate docs

Does not fetch docs. Next.js 16+ ships its full docs (markdown, matching your installed version) at `node_modules/next/dist/docs/`. This tool returns that path and how to read it, so the agent uses version-accurate docs instead of training-data guesses. On older Next.js, it recommends `npx @next/codemod@latest upgrade latest`.

Input: `topic` (optional), `project_path` (optional, defaults to cwd).

browser_eval — set up browser automation

Does not drive the browser. It detects whether `agent-browser` is installed and returns either the entry point (`agent-browser skills get core --full`) or the install steps (`npm install -g agent-browser`, then `agent-browser install`), so the agent runs the CLI directly.

Input: `task` (optional) — used only to tailor the guidance.

Migrating from 0.3.x

Starting in 0.4.0, `next-devtools-mcp` is a thin connector.

Changed:

• `nextjs_docs` no longer fetches docs over the network. It points the agent at the docs Next.js bundles at `node_modules/next/dist/docs/` (or recommends upgrading). The `nextjs-docs://llms-index` resource is removed.

Removed:

• `init` tool — it only enforced the old docs-fetch workflow.
• `upgrade_nextjs_16` and `enable_cache_components` tools and their prompts — now distributed as agent skills.
• All `cache-components://`, `nextjs16://`, and `nextjs-fundamentals://` resources — superseded by the bundled docs.

What remains: `nextjs_index`, `nextjs_call`, `nextjs_docs`, and `browser_eval`.

Privacy & Telemetry

`next-devtools-mcp` collects anonymous usage telemetry to improve the tool:

• Tool usage — which MCP tools are invoked (e.g. `nextjs_index`, `nextjs_call`)
• Error events — anonymous error messages when tools fail
• Session metadata — session ID, timestamps, basic environment (OS, Node.js version)

Not collected: your code, file contents or paths, personal data, credentials, or tool arguments (only tool names).

Local files live under `~/.next-devtools-mcp/` (anonymous `telemetry-id`, `telemetry-salt`, and a debug log `mcp.log`).

Opt out by setting the environment variable (add it to `~/.zshrc` / `~/.bashrc` to persist):

export NEXT_TELEMETRY_DISABLED=1

Delete local telemetry data anytime:

rm -rf ~/.next-devtools-mcp

Troubleshooting

`ERR_MODULE_NOT_FOUND` referencing `next-devtools-mcp/dist` — clear your npx cache and restart your MCP client. The server reinstalls fresh.

`[error] No server info found` — `nextjs_index` / `nextjs_call` need a running Next.js 16+ dev server:

1. Start it: `npm run dev`

2. Confirm Next.js 16+ (the `/_next/mcp` endpoint only exists there)

3. Verify it started without errors

`browser_eval` and `nextjs_docs` work without a dev server.

Local Development

git clone https://github.com/vercel/next-devtools-mcp.git
cd next-devtools-mcp
pnpm install
pnpm build

Point your MCP client at the local build:

{
  "mcpServers": {
    "next-devtools": {
      "command": "node",
      "args": ["/absolute/path/to/next-devtools-mcp/dist/index.js"]
    }
  }
}

Or with Codex:

codex mcp add next-devtools-local -- node dist/index.js

See the Next.js MCP documentation for how MCP works with Next.js and coding agents.

License

MIT