Model selector shows “GPT-5.1-Codex-Max” but session reports “GPT-5”

What version of Codex is running?

codex-cli 0.63.0

What subscription do you have?

Plus

Which model were you using?

GPT-5.1-Codex-Max

What platform is your computer?

Linux 6.11.9-100.fc39.x86_64 x86_64 unknown

What issue are you seeing?

Description of the issue:
Inside the VS Code Codex extension, selecting GPT-5.1-Codex-Max from the model selector does not match the model identity returned in chat.
Although the dropdown lists GPT-5.1-Codex-Max as available, the model responds as “GPT-5.” when asked for its current model name. This suggests a mismatch between the model configured in the UI and the actual model instantiated for the session.

Actual behavior:

Model selector shows GPT-5.1-Codex-Max

When queried (“what model are you running?”), the model replies “GPT-5.”
This inconsistency makes it unclear which model is truly running.

<img width="303" height="761" alt="Image" src="https://github.com/user-attachments/assets/af752e3b-766e-450a-bb5a-4f4eed07da84" />

What steps can reproduce the bug?

Steps to reproduce:

1. Open VS Code with the Codex extension.

1. In the sidebar/selector, choose GPT-5.1-Codex-Max.

1. Start a session.

1. Ask the model for its current model name.

1. Observe mismatch.

Date observed: 2025-12-01 22:19:33

What is the expected behavior?

When selecting GPT-5.1-Codex-Max in the Codex model dropdown, the active session should instantiate that model and report the same identifier.

Additional information

Environment: VS Code Codex extension

OS: Fedora 39 (Linux 6.11.9-100.fc39.x86_64)

Date observed: 2025-12-01 22:19:33