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.
Everything Browser Use is now managed by Hermes: the canonical binary
is the one install_cli() provisions into HERMES_HOME/bin, and every
resolution and provisioning site prefers it.
- _find_cli(): probe order flipped to managed bin -> PATH ->
user-level tool dir (then uvx across the same order). A user's own
uv tool install can no longer shadow the Hermes-managed copy with a
drifted version; side installs only matter when we have nothing.
- install_cli(): a browser-use on PATH no longer short-circuits the
install — only the managed copy does, so selecting any backend
provisions the copy Hermes controls and updates.
- _ensure_browser_use_cli() (hermes tools): drops its own PATH check
and always delegates to install_cli(), the single owner of the
managed-copy policy.
- install.sh / install.ps1: same short-circuit fix — only
HERMES_HOME/bin/browser-use counts as installed.
Follow-up to #86240 and #86320: with every non-Camofox backend
selection installing the CLI, managed-first closes the remaining
version-drift/shadowing class instead of guarding single sites.
Tests updated to pin the new contract: managed beats PATH and
user-local; PATH install does not satisfy install_cli; helper always
delegates. E2E-verified precedence chain with real files and a real
degraded-PATH install attempt.
Desktop/TUI workers can spawn with a minimal PATH that omits
~/.local/bin, the default location where uv tool install links the
browser-use binary. _find_cli() then failed to resolve an installed
CLI and Browser Use mode silently fell back to the built-in tools.
Probe the user-level tool dir (~/.local/bin on POSIX, APPDATA/uv/bin
on Windows) between PATH and the managed HERMES_HOME/bin, for both
the browser-use binary and the uvx fallback.
Salvaged from PR #83788 by @kimyxx onto current main; tests adapted
and extended with precedence and uvx coverage.
The Browser Use CLI became the default browser backend, but nothing
provisioned it: users without uv/uvx (field report from DongyangHe on
macOS) silently fell back to the built-in browser tools with no notice.
- install_cli() in tools/browser_use_cli.py: uv tool install browser-use
via the managed uv (bootstrapped on demand), linked into
$HERMES_HOME/bin (UV_TOOL_BIN_DIR)
- _find_cli() now also probes $HERMES_HOME/bin for browser-use/uvx —
Hermes' managed uv is not on the user's PATH
- hermes tools post_setup actually installs (Camofox standard) instead
of printing instructions
- install.sh / install.ps1 provision the CLI at install time
(best-effort, non-fatal, honors --skip-browser)
- CLI startup shows a one-line notice (24h rate-limited) when the
default backend downgraded to the built-in tools
An unset browser.backend ("") now resolves to Browser Use mode whenever
the browser-use CLI is runnable (installed binary or uvx); otherwise the
built-in browser tools are kept so browsing never silently breaks.
Camofox setups always keep the built-in tools (no CDP surface), and
backend: off (including YAML 1.1 bare off -> False) forces the built-in
stack. hermes tools row highlighting follows the same effective-mode
resolution, and tests/tools/ pins CLI discovery off so host uvx installs
can't flip built-in-browser tests.
Reframe (per review): browser.backend: browser-use is now a DRIVER over
whatever browser source is configured, not a competing backend choice.
- browser_exec resolves its CDP endpoint through the same chain the
built-in tools use: BU_* env override > BROWSER_CDP_URL/browser.cdp_url
(/browser connect) > the configured cloud provider via browser_tool's
_get_session_info() — sharing the per-task session cache, expiry
replacement, inactivity reaper, and atexit cleanup instead of
duplicating them. Live-validated against Browserbase (session created,
driven, reaped) and gateway-provisioned Browser Use cloud browsers.
- Direct-API Browser Use configs skip provider resolution (the CLI talks
to their cloud natively via BU_AUTOSPAWN); the Nous-gateway variant
resolves through the provider, so subscribers get CLI mode without a
raw BROWSER_USE_API_KEY.
- Camofox: only true fallback — Firefox-based, custom HTTP API, no CDP
surface (its own health probes fail on CDP-schema calls). Active
Camofox setups keep the built-in browser tools even with
backend: browser-use set.
- hermes tools picker: provider rows and the Browser Use row are no
longer mutually exclusive; selecting a provider keeps the driver
choice, and both rows highlight when composed.
- Docs updated for driver-over-source semantics.
Camofox is selected via CAMOFOX_URL env var, not browser.cloud_provider —
so a Camofox user with a stray BROWSER_USE_API_KEY in .env matched the
legacy-migration predicate (cloud_provider unset + key present) and got
silently flipped into CLI mode, losing browser_* / Camofox entirely
(browser_exec cannot drive Camofox: its HTTP API exposes no CDP endpoint,
and the browser-use harness is CDP-only against Chromium).
is_legacy_browser_use_cloud_config() now defers to is_camofox_mode().
Follow-ups on the salvaged Browser Use CLI integration (PR #66476):
- browser_exec runs model-written Python on the host. Strip it at
tool-definition time for sessions whose resolved toolsets exclude
'terminal' so terminal-less surfaces (locked-down messaging configs)
don't silently regain host code execution through the browser toolset.
Session-level gate in model_tools, not a check_fn (check_fn results are
TTL-cached process-wide across sessions).
- Replace the live 'browser-use skill' schema fetch with a pinned helpers
digest: no third-party version-drifting text in the prompt, byte-stable
schema across machines. A/B benchmarked (108 runs, opus-4.8 + kimi-k3,
6 multi-step web tasks x 3 arms x 3 reps): pinned digest matches the
full skill dump 36/36 vs 36/36 at ~equal tokens; both cut total task
tokens ~60% vs the legacy browser_* toolset.
- Docs note for the terminal gate; contributor mapping for salvage.
