Windows desktop: Bad Request after successful local tool calls

Codex desktop on Windows has repeatedly interrupted multi-step local image-editing tasks with “Bad Request” after successful tool calls.

Uploaded diagnostic feedback ID:
01a07b4a-bd88-7f12-9e13-c388e96b374a

Environment:

• Desktop package: OpenAI.Codex 26.901.6511.0
• Bundled app-server: 0.153.4
• Model: gpt-5.6-terra
• Reasoning effort: xhigh
• Authentication: ChatGPT login

Affected session:
01a07ea1-982f-7cd0-861c-6db59262335e

Failed turn:
01a07eec-cea6-79e3-ad8d-4a91f8fdd4ee

Recorded failure:

• Date: 2026-09-08. All times below are UTC+8.
• The final local PowerShell command completed successfully at 11:03:17.602, with exit code 0 and no stderr.
• At 11:03:20.301, the task_complete event contained this error:

{"message":"{"detail":"Bad Request"}","codex_error_info":"other"}

The event ended the task with an error; it did not indicate successful completion.

No numeric HTTP status, remote request ID, or failing endpoint was recorded. This turn had no compacted event. EPIPE/IPC disconnection was logged approximately 28 seconds after the error; its causal relationship is unknown.

Checks already performed:

• No clear local configuration error was found.
• A subsequent CLI test using the same login, model, and configuration successfully attached two PNG images, described their contents, executed a read-only command, and ended normally.
• A desktop attachment test also returned image observations and successful tool results.
• These short tests did not reproduce the original failure. No fix has been identified or applied.

Expected behavior: the turn should finish normally after successful tool calls.

Please correlate the uploaded diagnostics with the affected session and turn, investigate the failure, and advise on a fix or supported workaround.

Start with the uploaded diagnostic feedback for session 01a07ea1-982f-7cd0-861c-6db59262335e and failed turn 01a07eec-cea6-79e3-ad8d-4a91f8fdd4ee, correlating them with the task_complete error and subsequent EPIPE log. Compare the failing desktop flow with the successful CLI and desktop attachment tests; done means identifying the failing request or cause and documenting a verified fix or supported workaround.