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)
Tools
| Tool | What it does |
|---|
nextjs_index | Discover running Next.js dev servers and list each one's runtime MCP tools. |
nextjs_call | Call a runtime tool on a discovered server (errors, routes, logs, Server Actions). |
nextjs_docs | Gateway. Point the agent at version-accurate docs in node_modules/next/dist/docs/. |
browser_eval | Gateway. Point the agent at the agent-browser CLI for browser automation. |
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).
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 errorsget_logs — path to the dev log file (browser console + server output)get_page_metadata — routes, pages, component metadataget_project_metadata — project structure, config, dev server URLget_server_action_by_id — resolve a Server Action ID to its source file
Output: JSON listing discovered servers (port, PID, URL) and their tools.
Calls one runtime tool on a discovered server. Run nextjs_index first to find the port and tool name.
Input:
port (required) — dev server porttoolName (required) — runtime tool to invokeargs (optional) — arguments object, only if the tool requires them
{ "port": 3000, "toolName": "get_errors" }
Output: JSON with the tool's result. Upstream requests, including response-body reads, have a 60-second deadline. Cancelling an MCP request aborts its upstream network work; discovery also releases response bodies used only to detect the protocol.
Does not fetch docs. Recent Next.js releases bundle their docs (markdown, matching your installed version) at node_modules/next/dist/docs/. This tool checks for those files before returning reading instructions. If an installed release has no bundled docs (including early 16.x releases), it offers https://nextjs.org/docs as a fallback and asks the agent to verify APIs against the installed version. Missing dependencies receive installation guidance instead. On Next.js below 16, it recommends npx @next/codemod@latest upgrade latest.
Input: topic (optional), project_path (optional, defaults to cwd). The tool resolves next/package.json from that project, including hoisted workspace dependencies, and returns an absolute docsPath for the installed package.
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:
- Start it:
npm run dev
- Confirm Next.js 16+ (the
/_next/mcp endpoint only exists there)
- 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