Browser Use mode never read browser.engine: _resolve_backend_cdp() went
BU_CDP_* env -> CDP override -> cloud provider -> local Chrome, so
`engine: lightpanda` was a silent no-op on the default backend, and on
the built-in path it was skipped whenever a cloud provider, Camofox or a
CDP override was active without anyone saying so.
- browser_use_cli: when the engine is lightpanda and nothing with higher
precedence claimed the session, get a session from _get_session_info()
and export its endpoint as BU_CDP_URL; the browser is private to the
session key, so the own-tab preamble is skipped. The browser_exec
description gains a Lightpanda header (text-first, new_tab once then
goto_url — lightpanda-io/browser#1962).
- browser_tool: _create_local_session() spawns `lightpanda serve
--host 127.0.0.1 --port <free>` per session key (new
tools/browser_lightpanda.py), reusing the session cache, inactivity
reaper and atexit cleanup; a dead process is respawned on the next call;
orphans from a crashed Hermes are reaped through per-process records in
$HERMES_HOME/cache/browser-use/lightpanda/. New lightpanda_engine_status()
reports whether the engine is in effect or what shadows it.
- tools_config: "Lightpanda" row in the Browser Automation picker
(cloud_provider: local + engine: lightpanda; "Local Browser" resets the
engine to auto) with a binary-check post-setup.
- /browser status and hermes doctor print the engine state and, when it
is shadowed, the reason.
Adrià Arrufat