[Linux/Android] Luna Max reasoning effort missing on desktop; remote Max session displays as Medium

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

ChatGPT desktop (Powered by Codex & OWL), Version 26.803.81509, released 11 Aug 2026

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Nobara Linux 43 (Fedora-based), KDE Plasma 6.6.4, Wayland

Which model were you using?

GPT-5.6 Luna

What issue are you seeing?

On the native ChatGPT desktop app for Linux, GPT-5.6 Luna only offers reasoning effort up to Extra High. Max is not available.

However, when remotely controlling the same Codex session from the ChatGPT Android app, Max is available for Luna.

If I select Luna + Max from Android and then return to the same session in the Linux desktop app, the desktop app displays the session as Luna + Medium, rather than Max.

It is unclear whether the session is actually being downgraded from Max to Medium or whether this is only a UI/state representation problem.

This appears similar to #33805, which reported essentially the same cross-client behaviour on macOS/iOS, but this reproduction is on native Linux/Android.

What steps can reproduce the bug?

1. Open a Codex session in the native ChatGPT desktop app on Linux.
2. Select GPT-5.6 Luna.
3. Open the reasoning-effort selector.
4. Observe that the highest available option is Extra High; Max is absent.
5. Open/remote-control the same Codex session using the ChatGPT Android app.
6. Select Luna + Max.
7. Return to the same session in the Linux desktop app.
8. Observe that the desktop app now displays Luna + Medium.

What is the expected behavior?

• Max should be available for Luna in the Linux desktop app if it is supported for the account/model.
• A reasoning-effort selection made on another client should be preserved and represented correctly when the same session is opened on Linux.
• A Luna + Max session should not silently appear as Luna + Medium.

Additional information

Desktop environment: KDE Plasma 6.6.4
Display server: Wayland
Mobile client: ChatGPT Android app
Related issue: #33805 (macOS/iOS reproduction)

Start by reproducing the eight steps across the native Linux desktop app and ChatGPT Android app, comparing the reasoning-effort selector with the session state after choosing Luna + Max. Done means Max is available on Linux when supported and a Luna + Max selection made on Android remains represented as Max when the session returns to Linux.