Model selector is stuck on GPT-5.5 with medium intelligence in chats and some projects

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

Codex App 26.422.21637 (2056)

What subscription do you have?

ChatGPT Pro

What platform is your computer?

Darwin 25.4.0 arm64 arm

What issue are you seeing?

In the Codex App, the model selector appears to be restricted only in the initial/new-conversation state for Chats mode and for new conversations in some projects.

Before I send the first message in an affected chat/project conversation, the only available model/intelligence combination I can select is:

• gpt-5.5
• medium intelligence

I cannot switch to other models or other intelligence levels from the selector in that initial state, even though these options are expected to be available in the app.

After I send a message in the conversation, the selector appears to recover and I can choose other models/intelligence levels again.

This does not affect every project. So far I see it in Chats mode and when creating new conversations in some projects. Existing conversations, or conversations after the first message has been sent, may allow model selection normally.

This is still disruptive because the model/intelligence choice usually needs to be made before sending the first prompt. For example, I may want to start a new conversation with a cheaper/faster model or a different reasoning level, but the UI initially only exposes gpt-5.5 with medium intelligence.

Video placeholder:

https://github.com/user-attachments/assets/b814278b-cbb0-45bf-b07a-de4253b4da37

What steps can reproduce the bug?

1. Open the Codex App.
2. Go to Chats mode, or open one of the affected projects.
3. Start a new conversation, but do not send any message yet.
4. Click the model selector.
5. Observe the available model/intelligence options.
6. Try to select a model other than gpt-5.5, or an intelligence level other than medium.
7. Send a first message in the conversation.
8. Click the model selector again.

Observed result:

• Before the first message is sent, the selector only allows gpt-5.5 with medium intelligence.
• Other models/intelligence levels are not selectable from the UI in that initial state.
• After the first message is sent, the selector appears to recover and other options become selectable again.
• This happens in Chats mode and in some projects, but not necessarily every project.

What is the expected behavior?

The Codex App model selector should allow selecting the other models and intelligence levels available to my account/subscription before sending the first message in a new conversation.

Additional information

_No response_