browser-harness

name browser-harness description Direct browser control via CDP — automate, scrape, test, or interact with web pages by driving the user's already-running Chrome (or a Browser Use cloud browser). Use when the user wants to click, screenshot, fill forms, extract data, or navigate real web pages. Default to screenshots + coordinate clicks, not selector hunting. Requires the one-time `browser-harness` CLI install (see references/install.md). browser-harness Direct browser control via CDP. You drive the user's real browser with Python helpers run through the browser-harness command. Prerequisite (one-time — NOT part of the AI workflow) This skill is instructions only. It assumes the browser-harness command is already on $PATH . If command -v browser-harness fails, do the one-time install in references/install.md first, then continue. Installation and browser-connection setup are a prerequisite; once browser-harness <<'PY' … PY prints page info, never run install/connection steps again as part of normal work. Usage browser-harness << 'PY' new_tab( "https://docs.browser-use.com" ) wait_for_load() print (page_info()) PY Invoke as browser-harness — it's on $PATH after install. No cd , no uv run . Use the heredoc form for every multi-line command. It prevents shell quote mangling inside Python strings and JavaScript snippets. First navigation is new_tab(url) , not goto_url(url) — goto runs in the user's active tab and clobbers their work. Helpers are pre-imported and the daemon auto-starts; you never start/stop it manually unless you want to. What actually works Screenshots first. capture_screenshot() to understand the page, find visible targets, and decide whether you need a click, a selector, or more navigation. Clicking. capture_screenshot() → read the pixel off the image → click_at_xy(x, y) → capture_screenshot() to verify. Suppress the Playwright-habit reflex of "locate first, then click" — no getBoundingClientRect , no selector hunt. Drop to DOM only when the target has no visible geometry. Hit-testing happens in Chrome's browser process, so clicks pass through iframes / shadow DOM / cross-origin without extra work. Bulk HTTP. http_get(url) + ThreadPoolExecutor . No browser needed for static pages. After goto: wait_for_load() . Wrong/stale tab: ensure_real_tab() . Verification: print(page_info()) is the simplest "is this alive?" check; screenshots are the default way to verify whether a visible action worked. DOM reads: use js(...) for inspection/extraction when a screenshot shows coordinates are the wrong tool. Auth wall: redirected to login → stop and ask the user. Don't type credentials from screenshots. Raw CDP for anything helpers don't cover: cdp("Domain.method", params) . After every meaningful action, re-screenshot before assuming it worked. Remote / cloud browsers Use remote for parallel sub-agents (each gets an isolated browser via a distinct BU_NAME ) or on a headless server. BROWSER_USE_API_KEY must be set. browser-harness << 'PY' start_remote_daemon( "work" ) # clean cloud browser; profileName=/profileId= to reuse a logged-in profile PY BU_NAME=work browser-harness << 'PY' new_tab( "https://example.com" ) print (page_info()) PY start_remote_daemon prints a liveUrl so the user can watch. Running remote daemons bill until timeout. Interaction skills (progressive disclosure) If you struggle with a specific UI mechanic, read the matching file under ${CLAUDE_PLUGIN_ROOT}/interaction-skills/ before inventing an approach. Available: browser-wall, connection, cookies, cross-origin-iframes, dialogs, downloads, drag-and-drop, dropdowns, iframes, network-requests, print-as-pdf, profile-sync, screenshots, scrolling, shadow-dom, tabs, uploads, viewport. Task-specific edits For task-specific helper additions, edit ${CLAUDE_PLUGIN_ROOT}/agent-workspace/agent_helpers.py . Keep core helpers short. Domain skills (opt-in) Community per-site playbooks live in ${CLAUDE_PLUGIN_ROOT}/agent-workspace/domain-skills/<host>/ and are off by default . Set BH_DOMAIN_SKILLS=1 to enable them; when enabled and the task is site-specific, read every file in the matching <site>/ directory before inventing an approach. Design constraints Coordinate clicks default. Input.dispatchMouseEvent goes through iframes/shadow/cross-origin at the compositor level. Connect to the user's running Chrome. Don't launch your own browser. Prefer compositor-level actions (screenshots, coordinate clicks, raw key input) over framework/DOM hacks. Reach for interaction-skills/ only when those are the wrong tool.