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."
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:
How it works
install.mdconnects the agent to your browser.SKILL.mdteaches it the browser workflow.src/browser_harness/stays protected while the agent writes reusable helpers in its local workspace.
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