Reproduces with pip install openai-codex --no-deps (lightweight install
that skips the pinned openai-codex-cli-bin runtime) or any host where
the codex CLI is installed via npm i -g @openai/codex / Homebrew /
manual download. Studio constructs AsyncCodex(config=AppServerConfig(
env=...)) without codex_bin, so the SDK runs _installed_codex_path
which 'from codex_cli_bin import bundled_codex_path' and raises
FileNotFoundError: Unable to locate the pinned Codex runtime. Install
the published SDK build with its openai-codex-cli-bin dependency, or
set AppServerConfig.codex_bin explicitly. -- even though a perfectly
good codex is on PATH and was the binary the availability probe
already verified.
Fix: resolve shutil.which("codex") and pass it as
AppServerConfig(codex_bin=...). The PR's availability probe already
returns that exact path in /api/codex/status.cli_path, so we are
giving the SDK back the binary the user can see in the Connections
form. Falls back to AppServerConfig(env=...) (no codex_bin) when the
SDK build does not accept the kwarg yet, and falls back to PATH lookup
returning None on hosts without codex on PATH (in which case the
availability probe would have reported installed=false and Studio
never gets here).
Test fixture: also inject the fake module under openai_codex (the
canonical name the production importer prefers) so the test does not
silently exercise the real SDK on developer venvs that have
pip install openai-codex already done.
End-to-end verified live: pip install -e openai/codex sdk/python plus
Studio with codex CLI on PATH yielded ROUND_TRIP_OK streaming for
gpt-5.4-mini through the OpenAI-compat completions route.
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