Browser Harness

Browser Harness is an open source harness from Browser Use that connects a large language model directly to a real Chrome browser through a single Chrome DevTools Protocol websocket. It is deliberately thin. Rather than shipping a fixed catalogue of browser actions, it lets the agent write the helper functions it is missing while it works, so when a task needs something new, such as uploading a file, the agent adds that helper to its local workspace and reuses it on later tasks. It is aimed at developers who already work with coding agents such as Claude Code or Codex and want those agents to operate the browser they are logged into. Setup is a prompt pasted into the coding agent, which installs the package with uv on Python 3.12, registers the skill and asks the user to enable remote debugging in Chrome. The core package stays protected while generated helpers live in the agent's own workspace. An included MCP server exposes the browser control helpers as tools over stdio, so any MCP client, including Cursor and Devin, can drive the browser without a second automation layer. Local recordings of browser sessions are optional and off by default. The harness itself is free under the MIT licence. Running it against the local browser costs nothing beyond the model the user supplies. For many browsers in parallel, with proxies, stealth, CAPTCHA solving and live previews, Browser Use points users to its paid cloud browsers, billed on the Browser Use pay as you go rates, or to a dedicated Browser Use Box that runs agents continuously.