ChatGPT Desktop Codex selects GPT-5.6 Sol but runtime rejects it; context compaction loops

What version of the Codex App are you using (From “About Codex” dialog)?

ChatGPT Desktop app — bundled Codex CLI 0.153.4

What subscription do you have?

ChatGPT Pro (signed in with a ChatGPT account)

What platform is your computer?

27.0.0 arm64 arm

What issue are you seeing?

Summary

In the ChatGPT Desktop app, an existing Codex chat shows “5.6 Sol, extra high” in the model selector.

However, the task returned this runtime error:

“The 'gpt-5.6-sol' model is not supported when using Codex with a ChatGPT account.”

The same chat then repeatedly attempted automatic context compaction and reconnecting (2/2), but failed with:

“Error running remote compact task: Codex ran out of room in the model's context window. Start a new thread or clear earlier history before retrying.”

Other Codex chats are working normally. This affected chat remains stuck.

I already submitted in-app feedback. I can provide the feedback/session ID privately if needed.

What steps can reproduce the bug?

In-app feedback was submitted; identifier available privately upon request.

What is the expected behavior?

The model selector should show only models that are actually available to the signed-in ChatGPT account.

If a chat exceeds the context window, Codex should provide a reliable recovery path without repeated failed compaction and reconnect attempts.

Additional information

Start by reproducing the issue in the ChatGPT Desktop app with bundled Codex CLI 0.153.4, checking the model selector and the context-compaction/reconnect behavior. Compare the selected model with the signed-in ChatGPT account's supported models; done means unavailable models are not shown and an over-limit chat has a reliable recovery path without repeated failed attempts.