[Kamilbenkirane]

A failed BFL task can come back from the poll endpoint as a non-2xx response with its status in the JSON body. BFLImagesClient._make_request called _handle_error_response before reading that body, so such a task raised httpx.HTTPStatusError ("bfl API error: {...}"). It should raise the ValueError that names the BFL status, as the loop already does for Error, moderation, No Card Generated (#512) and Task not found. Two BFL pages document this:

• FLUX 3 image generation: "A failed task can come back as HTTP 503 with a normal JSON body. Read status from the body before treating a 503 as a retryable outage."
• FLUX Video Edit, on the same polling flow: such requests "fail with HTTP 422, status: "Error", and an explanation in details.error."

The get_result schema in the OpenAPI spec (ResultResponse: id, status, result, progress, details) is the body these responses carry.

Fix:

• src/celeste/providers/bfl/images/client.py, BFLImagesClient._make_request: the poll loop now parses the JSON body first and checks Ready and the existing terminal statuses. It calls _handle_error_response only after those checks.
  • A non-2xx body with a terminal status raises the existing ValueError, with the status and error/details.
  • Every other non-2xx response still raises httpx.HTTPStatusError as before: a non-JSON outage page, {"detail": ...}, a 429, or an in-progress status.
• A successful 2xx body that isn't JSON still raises JSONDecodeError. The status list and messages are unchanged.

Overlap: draft #524 renames this file to providers/bfl/flux/client.py and #521 builds on it. git merge-tree shows this change applies to both branches without conflicts.

Validation:

• make ci passes: Ruff, format, mypy, Bandit, 744 unit tests.

• Live: test_generate[bfl-flux-2-klein-4b-parameters3] passes on this branch (POST https://api.bfl.ai/v1/flux-2-klein-4b, aspect_ratio 256x1024, polled to Ready).

• Local, uncommitted, with stubbed poll responses:

  Poll response	main	This branch
  503 {"status":"Error","details":{...}}	HTTPStatusError	ValueError: bfl image generation failed (Error): {...}
  422 {"status":"Error",...}	HTTPStatusError	ValueError
  503 HTML, 429 {"detail":...}, 500 {"status":"Pending"}	HTTPStatusError	HTTPStatusError (unchanged)
  200 Pending, then Ready	returns	returns (unchanged)

• There is no unit test. One would have to stub the transport, and house rules keep that to tests/unit_tests/test_http.py.

• CHANGELOG is unchanged, following the fix PRs merged since the v1.0.0 tag (fix(bfl): add match_input to the flux-3-image quality choices #548–fix(openai): remove the shut-down gpt-image-1 registration #553).