browser-harness-skill

Browser Harness Skill

Controls the user's real Chrome through raw CDP (browser-use/browser-harness). Unlike the browser tool (accessibility tree + @eN refs), this tool is vision-first: you look at screenshots and click coordinates, with js() for reading the DOM. Use it when you need the user's logged-in browser, sites that fight automation frameworks, or interactions the structured tool can't express.

Core Workflow

The see -> act -> verify loop, written as Python in operation: run_python:

1. capture_screenshot() to SEE the page (the returned path is an image you can view)
2. click_at_xy(x, y) at coordinates you identified from the screenshot
3. wait_for_load() after anything that navigates
4. capture_screenshot() again to verify the result
5. js(...) when you need exact text/attributes instead of pixels

{"operation": "run_python", "code": "ensure_real_tab()\ngoto_url('https://example.com')\nwait_for_load()\nprint(page_info())"}

browserHarness Tool

Field	Type	Required	Description
operation	string	Yes	run_python (primary), goto, screenshot, js, tabs, doctor
code	string	run_python	Python executed with helpers pre-imported. Print a JSON object as the LAST line for structured output
url	string	goto	URL to open
expression	string	js	JavaScript to evaluate in the page
full_page	bool	screenshot	Capture the full scrollable page (default: false)
timeout	int	no	Script timeout in seconds (default: 60)

Helper Reference (inside run_python)

All pre-imported — never import them.

Navigation & tabs

• goto_url(url) — navigate current tab
• new_tab(url="about:blank") / close_tab(target=None) / switch_tab(target)
• list_tabs(include_chrome=True) — enumerate open tabs
• current_tab() / ensure_real_tab() — make sure a real page tab is focused (call first!)
• page_info() — {url, title, w, h, sx, sy, pw, ph} (viewport + scroll + page size)
• iframe_target(url_substr) — target for js/interaction inside an iframe