Followups on the post-merge review pass for the Codex SDK chat
provider. Verified against codex-cli 0.133.0 + the upstream
`openai/codex` Rust + Python sources, then pinned each fix with
a regression test in `test_codex_provider.py` (24/24 passing).
* Probe both `openai_codex` (canonical upstream Python package at
`openai/codex/sdk/python`) and the legacy `codex_app_server`
alias. Without this the availability probe always reported
`sdk_importable: false` even when the SDK was installed, so the
provider was permanently hidden.
* Switch the device-auth and login-status invocations from
`codex auth login --device-auth` / `codex auth status` to the
real upstream subcommands `codex login --device-auth` and
`codex login status`. The former path returns
`unrecognized subcommand 'auth'` on a real CLI.
* Strip ANSI control sequences before extracting the device URL
(upstream wraps the URL in `\x1b[34m...\x1b[0m`) and tighten the
pattern to the canonical `.../codex/device` shape. Also surface
the one-time code as a `device_code` SSE event so the UI can
show it alongside the URL.
* Fix `_detect_logged_in` substring footgun: `"logged in" in
combined` matched inside `"not logged in"`, flipping logged-out
users to logged-in. Anchor on word boundaries with negative
prefixes winning regardless of return code.
* Cancel in-flight fan-out workers on SSE disconnect. Previously
every parallel Codex turn ran to completion against a
disconnected client and burned quota; now `_stream_codex_parallel`
cancels its worker + drain tasks in a try/finally on
`CancelledError`/`GeneratorExit`.
* Tear down the device-login subprocess on disconnect via
`start_new_session=True` + `os.killpg(SIGTERM)` (Unix) or
`CREATE_NEW_PROCESS_GROUP` + `CTRL_BREAK_EVENT` (Windows), with
a bounded `proc.wait()` and `proc.kill()` fallback. Previously
`finally: await proc.wait()` blocked the SSE close path because
`codex login --device-auth` only exits on user action.
* Render the full conversation transcript in `_last_user_prompt`
instead of returning only the most recent user message. The PR
opens a fresh thread per request so prior assistant turns were
dropped, degrading multi-turn chats to single-shot prompts.
Single-turn input is unchanged.
* Make `ChatCompletionRequest.parallel_calls` default to 1 (`int`
with `ge=1, le=20`) instead of `Optional[int] = None`. The
runtime already coerced `None` -> 1, but the schema now matches
the documented `[1, 20]` range.
* Replace the registry's hardcoded `default_models` (which
contained `o3`, not in the upstream catalog) with the current
`gpt-5.5 / 5.4 / 5.4-mini / 5.3-codex / 5.2` set from
`codex-rs/models-manager/models.json`.
* Stop echoing `str(exc)` in SSE error frames in both
`routes/inference.py` and `routes/codex.py`. The Codex SDK can
raise with local paths, env-var content, or traceback fragments
(CodeQL `py/information-exposure-through-exception`). Surface a
generic message + `exception_type` discriminator; log the full
reason server-side via `logger.error(..., exc_type=..., error=...)`.
Doc / comment updates throughout to refer to `codex login` /
`openai_codex` rather than the older incorrect strings.
Tested: pytest 24 cases in `test_codex_provider.py` (the original
14 + 10 new `TestCodexHardenedRegressions`) plus the rest of the
Studio-backend test suite the PR touches (209 passing). Also
verified live against Studio launched from this branch on a
Blackwell B200 via `UNSLOTH_STUDIO_HOME=$WORKSPACE/temp/...
./install.sh --local` then a Playwright probe.
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