Next.js 16 and later ship their full documentation inside the installed package, and nextjs_docs reads from there — so the answer tracks the version in your node_modules, not the version in the model's training data. nextjs_index then bridges to the dev server that is already running, which is where the app's own diagnostics live.
Vercel's Next.js DevTools server, four tools: it finds the version-accurate docs that Next.js 16 and later ship inside node_modules/next/dist/docs/, discovers the Next.js dev servers running on the machine and the MCP tools each exposes, calls those tools by port and name, and sets up browser work through the agent-browser CLI.
- Find the documentation that matches this project's installed Next.js rather than whatever the model remembers (nextjs_docs, taking project_path and topic).
- Discover every running Next.js development server and list the MCP tools it exposes (nextjs_index).
- Call a tool on a specific dev server by port, tool name and arguments (nextjs_call).
- Get browser automation set up for the project through the agent-browser CLI (browser_eval).
A Next.js project on the machine, Node.js to run the server, and a running dev server for the tools that talk to one.
One command — npx -y next-devtools-mcp@latest