In one case I had to upgrade my Antigravity GUI to see new models, I guess because of an API change.

At the same time, the CLI saw the new models without any change. Possibly that was just because my CLI install was newer than the GUI one. (Edit: oh, it's because my CLI autoupdates. Autoupdates for the GUI on Linux in an AppImage is... messy.)

Edit: But in this case:

> Gemini 4 Carbon is available via the API in Google AI Studio and Gemini for business for all paying developers and enterprises

I.e. Seems to be API only right now.

I found out when I opened Gemini app on phone and it showed Carbon Medium as default