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Browser Harness

  • 283 installs
  • 16.5k repo stars
  • Updated August 3, 2026
  • browser-use/browser-harness

browser-harness is a skill that provides direct CDP browser control for automation, scraping, testing, and site work via local Chrome or Browser Use cloud daemons.

About

This skill gives an agent direct browser control over the Chrome DevTools Protocol for automation, scraping, testing, and site work. A developer uses it to attach to local Chrome or spin up Browser Use cloud daemons, then screenshot, click by coordinates, and run JS or raw CDP. It matters when tasks span iframes, shadow DOM, or cross-origin frames where compositor-level clicks pass through.

  • Direct browser control via CDP with coordinate clicks and raw cdp() calls
  • Local Chrome attach or Browser Use cloud remote daemons
  • Optional per-site domain skills gated by BH_DOMAIN_SKILLS=1

Browser Harness by the numbers

  • 283 all-time installs (skills.sh)
  • Ranked #501 of 2,715 Automation & Workflows skills by installs in the Skillselion catalog
  • Data as of Aug 5, 2026 (Skillselion catalog sync)
At a glance

browser-harness capabilities & compatibility

Local Chrome control is free; Browser Use cloud remote daemons bill until stopped or timed out

Capabilities
browser automation · web scraping · testing
Works with
chrome
Use cases
web scraping · testing · web search
Runs
Local or remote
Pricing
Bring your own API key
From the docs

What browser-harness says it does

Direct browser control via CDP.
SKILL.md
Use Browser Use cloud for headless servers, parallel sub-agents, or isolated work.
SKILL.md
CDP mouse events pass through iframes/shadow/cross-origin at the compositor level.
SKILL.md
npx skills add https://github.com/browser-use/browser-harness --skill browser-harness

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Listed on Skillselion
Installs283
repo stars16.5k
Last updatedAugust 3, 2026
Repositorybrowser-use/browser-harness

What it does

Control a browser directly via CDP to automate, scrape, or test any website using local Chrome or Browser Use cloud.

Who is it for?

Coordinate-based CDP browser automation across iframes, shadow DOM, and cross-origin frames

Skip if: Simple accessibility-tree-only automation with no CDP or coordinate control

When should I use this skill?

Any web interaction is needed: automation, scraping, testing, or site/app work.

What you get

A completed web task driven by CDP coordinate clicks, screenshots, and helpers.

  • Automated browser task output

By the numbers

  • 17 interaction-skill topics listed
  • Domain skills gated by BH_DOMAIN_SKILLS=1

Files

SKILL.mdMarkdownGitHub ↗

browser-harness

Direct browser control via CDP. For task-specific edits, use agent-workspace/agent_helpers.py. For setup, install, or connection problems, read https://github.com/browser-use/browser-harness/blob/main/install.md.

Domain skills are off by default. Set BH_DOMAIN_SKILLS=1 to enable them; see the bottom section.

If `BH_DOMAIN_SKILLS=1` and the task is site-specific, read every file in the matching `$BH_AGENT_WORKSPACE/domain-skills/<site>/` directory before inventing an approach.

Usage

browser-harness <<'PY'
print(page_info())
PY
  • Invoke as browser-harness. Use heredocs for multi-line commands.
  • Helpers are pre-imported. run.py calls ensure_daemon() before exec.
  • First navigation is new_tab(url), not goto_url(url).
  • The normal local flow attaches to the running Chrome/Chromium CDP endpoint. No browser ids or local profile selection.

Local Chrome

If the daemon cannot connect, run diagnostics:

browser-harness --doctor

If Chrome remote debugging is not enabled, the harness opens:

chrome://inspect/#remote-debugging

Ask the user to tick "Allow remote debugging for this browser instance" and click Allow if Chrome shows a permission popup. Then retry the same browser-harness command.

Remote Browsers

Use Browser Use cloud for headless servers, parallel sub-agents, or isolated work. Authenticate once:

browser-harness auth login

Or import a key safely:

browser-harness auth login --api-key-stdin

Pick a short made-up name; r7k2 below is just a placeholder:

browser-harness <<'PY'
start_remote_daemon("r7k2")
PY

BU_NAME=r7k2 browser-harness <<'PY'
new_tab("https://example.com")
print(page_info())
PY

When the task is done and a cloud browser is still running, ask directly: "Should I close this browser now?" If yes, run stop_remote_daemon(name). Remote daemons bill until they stop or time out.

Do not start a remote daemon and then keep using the default daemon. Use the same name for BU_NAME.

Cloud profile cookie sync reference: https://github.com/browser-use/browser-harness/blob/main/interaction-skills/profile-sync.md.

Page Workflow

  • Screenshots first: use capture_screenshot() to understand visible state.
  • Clicking: screenshot -> read pixel -> click_at_xy(x, y) -> screenshot again.
  • After navigation, call wait_for_load().
  • If the current tab is stale or internal, call ensure_real_tab().
  • Use js(...) for DOM inspection or extraction when coordinates are the wrong tool.
  • Login walls: stop and ask. Exception: use available SSO automatically when Chrome is already signed in; still stop for passwords, MFA, consent, or ambiguous account choice.
  • Raw CDP is available with cdp("Domain.method", ...).

Interaction Skills

If you get stuck on a browser mechanic, check https://github.com/browser-use/browser-harness/tree/main/interaction-skills.

  • connection.md
  • cookies.md
  • cross-origin-iframes.md
  • dialogs.md
  • downloads.md
  • drag-and-drop.md
  • dropdowns.md
  • iframes.md
  • network-requests.md
  • print-as-pdf.md
  • profile-sync.md
  • screenshots.md
  • scrolling.md
  • shadow-dom.md
  • tabs.md
  • uploads.md
  • viewport.md

Design Constraints

  • Coordinate clicks default. CDP mouse events pass through iframes/shadow/cross-origin at the compositor level.
  • Keep the connection model simple: use the default daemon, BU_NAME, BU_CDP_URL, BU_CDP_WS, or start_remote_daemon(...).
  • Core helpers stay short. Put task-specific helper additions in $BH_AGENT_WORKSPACE/agent_helpers.py.

Gotchas

  • chrome://inspect/#remote-debugging must be enabled for local Chrome control.
  • Chrome may show an "Allow remote debugging?" popup; wait for the user to click Allow.
  • Omnibox popups are not real work tabs.
  • CDP target order is not Chrome's visible tab-strip order.
  • BU_CDP_URL is an HTTP DevTools endpoint; the daemon resolves it to WebSocket.
  • Ask before leaving cloud browsers running; stop them with stop_remote_daemon(name) or PATCH /browsers/{id} {"action":"stop"}.

Domain Skills

Only applies when BH_DOMAIN_SKILLS=1. Otherwise ignore domain skills.

When enabled, search $BH_AGENT_WORKSPACE/domain-skills/<host>/ before inventing an approach. goto_url(...) returns up to 10 skill filenames for the navigated host.

Related skills

FAQ

How does the first navigation work?

The first navigation is new_tab(url), not goto_url(url), and the harness attaches to the running Chrome/Chromium CDP endpoint.

When should I use a remote daemon?

Use Browser Use cloud for headless servers, parallel sub-agents, or isolated work, and stop it when done since remote daemons bill until they stop or time out.

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