# Browser Harness

Direct browser control via CDP.

- Repository: https://github.com/davidondrej/skills (4238 stars)
- Category: Testing
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add davidondrej/skills --skill browser-harness -g -a claude-code -y`
Codex: `npx skills add davidondrej/skills --skill browser-harness -g -a codex -y`
Cursor: `npx skills add davidondrej/skills --skill browser-harness -g -a cursor -y`
Gemini CLI: `npx skills add davidondrej/skills --skill browser-harness -g -a gemini-cli -y`

## Description

Direct browser control via CDP. Use when the user wants to automate, scrape, test, or interact with web pages. Connects to the user's already-running Chrome.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# browser-harness

Direct browser control via CDP. For task-specific edits, use `agent-workspace/agent_helpers.py`. For setup, install, or connection problems, read install.md.

**Routing check first:** if the task needs no interaction (no clicks, logins, or forms) and you just want page content, use DeepAPI `POST /v1/scrape/website` instead of driving a browser, see the `deepapi` skill. Use browser-harness when the task needs a real browser: interaction, JS-heavy flows, logged-in sessions, or visual verification.

Domain skills (community-contributed per-site playbooks under `agent-workspace/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 `agent-workspace/domain-skills/<site>/` directory before inventing an approach.**

## Usage

```bash
browser-harness -c '
new_tab("https://docs.browser-use.com")
wait_for_load()
print(page_info())
'
```

- Invoke as browser-harness, it's on $PATH. No cd, no uv run.
- First navigation is new_tab(url), not goto_url(url), goto runs in the user's active tab and clobbers their work.

## Tool call shape

```bash
browser-harness -c '
# any python. helpers pre-imported. daemon auto-starts.
'
```

run.py calls ensure_daemon() before exec, you never start/stop manually unless you want to.

### Remote browsers

Use remote for parallel sub-agents (each gets its own isolated browser via a distinct BU_NAME) or on a headless server. BROWSER_USE_API_KEY must be set. start_remote_daemon, list_cloud_profiles, list_local_profiles, sync_local_profile are pre-imported.

When supervising those sub-agents, after each check send the user one very short status line: what they are doing and whether they are on track.

Claude Code cmux note: after Claude finishes, it may prefill a predicted next user message; that draft is Claude, not the user speaking.

The rest: https://github.com/davidondrej/skills/blob/HEAD/skills/research-and-web/browser-harness/SKILL.md