Lightpanda MCP Server

A small, dependency-free Model Context Protocol server in Go that lets AI agents (Claude Code, Cursor, Windsurf, OpenCode, and other MCP clients) fetch pages and render them with Lightpanda, a lightweight headless browser built for automation.

Why this exists

Agents that browse the web need two things: the raw HTML of a page, and the page as a browser would see it after JavaScript runs. Full Chrome is heavy for that job. Lightpanda renders pages with a much smaller footprint, and this server exposes it to any MCP client over stdio with a deliberately small, safe surface:

• untrusted input never reaches a shell or an interpreter: URLs are validated (http/https with a host) and passed to the Lightpanda binary as a single argument;

• responses are size-limited and time-bounded;

• the server never starts background processes or opens network listeners on its own.

Related MCP server: SlimAtlas AI

Tools

Install

Requires Go 1.22+. For rendering, install the Lightpanda binary from lightpanda.io and make sure it is on PATH (or set LIGHTPANDA_BIN).

go install github.com/Brilhante29/lightpanda-mcp-server@latest

The npm, Bun, and PyPI packages announced in earlier versions of this README were never published; Go is the supported distribution.

Configure your MCP client

{
  "mcpServers": {
    "lightpanda": {
      "command": "lightpanda-mcp-server",
      "env": { "LIGHTPANDA_BIN": "lightpanda" }
    }
  }
}

If you run a Lightpanda CDP server for other tools, bind it to localhost (lightpanda serve --host 127.0.0.1 --port 9222): a CDP endpoint gives full control of the browser to anyone who can reach it.

Development

gofmt -l .
go vet ./...
go test -race ./...

The tests cover URL validation, argument construction for the Lightpanda subprocess, HTTP fetching against a local server, and the JSON-RPC handling of tool calls, malformed lines, and unknown methods. CI runs the shared reusable Go workflow.

Security notes

Version 1.1 removed three behaviors from the first release:

• a JavaScript execution tool that interpolated the URL and script into Node.js source, which allowed code execution on the host;

• a Node.js implementation that passed URLs to a shell command;

• automatic launching of a Lightpanda daemon bound to 0.0.0.0.

JavaScript execution may return later through a CDP client that sends the script as data, never as source code.

Roadmap

• Markdown and accessibility-tree extraction from the rendered DOM.

• Script evaluation through CDP with explicit opt-in.

• Release binaries for Linux, macOS, and Windows.

Related work

• llm-agent-eval: measuring tool-using LLM agents from observed traces.

• rag-knowledge-base: a retrieval layer with reproducible evaluation.

Author

Guilherme Brilhante, software engineer working on scalable backends and production AI. LinkedIn · GitHub · Publications

License

MIT. Lightpanda is a separate project with its own license.