browser-harness README

The project's README from github.com/browser-use/browser-harness. As one markdown file: README.md.

Browser Harness

Browser Harness ♞

Connect an LLM directly to your real browser through one editable CDP websocket. The agent writes missing helpers as it works, so the harness improves with every task.

Try browser-harness in Browser Use Cloud or paste the setup prompt into your coding agent.

  ● agent: wants to upload a file
  │
  ● agent-workspace/agent_helpers.py → helper missing
  │
  ● agent writes it                         agent_helpers.py
  │                                                       + custom helper
  ✓ file uploaded

You will never use the browser again.

See it work

Task: "Open my X profile, find my latest 20 video posts, and download them."

Download my latest 20 X videos

Setup prompt

Paste into Claude Code or Codex:

Install or upgrade browser-harness to the latest stable version with uv using Python 3.12, register the skill from `browser-harness skill`, and connect it to my browser. Ask whether I want local browser recordings enabled; default to no and preserve my existing preference on upgrades. Follow https://github.com/browser-use/browser-harness/blob/main/install.md if setup or connection fails.

The agent will open chrome://inspect/#remote-debugging. On first setup, tick the checkbox so the agent can connect to your browser:

Remote debugging setup

How it works

Scale with Browser Use Cloud

Use your local browser for logged-in, personal work. When you want many browsers in parallel—with live previews, proxies, stealth, CAPTCHA solving, and more—scale with Browser Use Cloud.

MCP server

browser-harness-mcp exposes the browser control helpers as MCP tools over stdio, so any MCP client (Claude Code, Devin, Cursor, etc.) can drive the browser without writing a second CDP layer. See docs/MCP.md for setup and client configuration.

Contributing

Bug fixes, documentation improvements, and agent-generated domain skills are welcome. See CONTRIBUTING.md.

The Bitter Lesson of Agent Harnesses · Web Agents That Actually Learn

browser-harness (browser-use/browser-harness)

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18.5K ·GitHub
Browser-harness
What is this?Browser Harness connects an LLM-based coding agent directly to your real browser through an editable CDP websocket, letting the agent complete real browser tasks (like finding and downloading your latest posts) while writing its own reusable helpers so it keeps improving with each task.
Is this a standalone app, or something I plug into my coding agent?It is not a separate application - it is a harness made of instruction files (install.md and SKILL.md) that you paste into an existing coding agent like Claude Code or Codex, teaching it how to drive your browser.
How do I get it running?Paste the setup prompt into Claude Code or Codex; the agent then opens chrome://inspect/#remote-debugging, and on first run you tick the checkbox so it can connect to your real browser.
Which coding agents or clients can drive the browser with this?It is built to be pasted directly into Claude Code or Codex, and any MCP-compatible client (Claude Code, Devin, Cursor, etc.) can also use it through the included browser-harness-mcp server over stdio.
Can the agent mess with the harness's own core code while it learns?No - the agent writes new reusable helpers into its own local workspace as it learns tasks, but the core src/browserharness/ directory stays protected from being overwritten.
Is the agent working inside my own logged-in browser sessions?Yes - the local setup is meant to drive your real, logged-in browser for personal work; running many isolated browsers instead of your own is an opt-in cloud feature, not the default.
What does Browser Use Cloud add on top of the local setup?It is the hosted scaling option for when you need many browsers running in parallel, with live previews, proxies, stealth mode, and CAPTCHA solving, instead of just driving your single local Chrome.
What is browser-harness-mcp for?It is an MCP server that exposes the browser-control helpers as MCP tools over stdio, so MCP clients like Claude Code, Devin, or Cursor can drive the browser without building their own CDP integration.
What are similar projects?browser-use, stagehand, scout, nanobrowser, web-ui, invisible_playwright_mcp, Endoplexity, SystemOneHarness
Which topics is it in?cloud-browser, browser-agent, web-automation, browser-use, cdp, vps, chrome, agent-harness, playwright, harness, browser-automation, cursor
Creator
browser-use
Size
4.8 MB
Stars
18.5K
Updated
CommitOct 15Releasev0.1.13Sep 04
Age
6mo
Commits · 90 Days