autoreg-skills-max/skills/windows-browser-automation/references/browser-use-security-watchdog-patch.md

browser-use SecurityWatchdog patch for real Comet profiles

browser-use 0.13.x closes existing file:// tabs as "disallowed" on attach. This destroys the user's open local-file tabs in their real Comet profile.

Patch (call before BrowserSession.start())

def patch_browser_use_security_watchdog():
    """Do not let browser-use close existing local/browser-scheme tabs on attach."""
    try:
        from browser_use.browser.watchdogs.security_watchdog import SecurityWatchdog
        if getattr(SecurityWatchdog, '_comet_agent_file_scheme_patch', False):
            return
        original = SecurityWatchdog._is_url_allowed
        def patched(self, url: str) -> bool:
            if isinstance(url, str) and url.startswith(('file://', 'chrome://', 'devtools://', 'edge://', 'comet://')):
                return True
            return original(self, url)
        SecurityWatchdog._is_url_allowed = patched
        SecurityWatchdog._comet_agent_file_scheme_patch = True
    except Exception as e:
        print(f'WARN: browser-use security patch skipped: {e}')

Why it happens

SecurityWatchdog.on_TabCreatedEvent checks every tab URL against _is_url_allowed. When allowed_domains is None (default), _is_url_allowed allows about:blank, chrome://new-tab-page/, chrome://newtab/, data:, and blob: — but NOT file://. So any existing file:// tabs in the real Comet profile get detected as "disallowed" and closed.

The patch adds file://, chrome://, devtools://, edge://, comet:// to the allowlist.

Alternative

Pass allowed_domains=['*'] to BrowserSession — but this enables glob-pattern matching which has its own caveats. The monkeypatch is more surgical.