The browser-use CLI runs under its own Python (uv tool / uvx), which
can differ from Hermes's venv interpreter. PYTHONPATH/PYTHONHOME
inherited from the agent process point at Hermes's venv
site-packages, and a child interpreter honors them ahead of its own —
so the CLI imported compiled C-extensions (pydantic_core) built for
the wrong interpreter and crashed with ABI mismatch /
ModuleNotFoundError (issues 83427, 84841, 86006, 86104; hits the
desktop backend on py3.14 and any shell exporting PYTHONPATH).
Strip both vars in _base_subprocess_env() — the CLI manages its own
environment and never needs Hermes's import path.
Salvaged from PR 83471 by Benjamin (@n1majne3), the earliest of two
independent fixes (also PR 84022 by @jklance16, PYTHONPATH-only);
regression test covers both vars and preserves unrelated env.
Benjamin