I checked gemini, set it to "gemini 4 argon" and it offered me Pro and Ultra to get access. I checked the normal plans, saw there is also plus.

Okay, so I'll get Pro to try it.

I subscribe.

No gemini 4.

The most generous reading I have is that it's a mistake. But I also downloaded the PC app, and now I really wonder why I did that, it seems to offer nothing beyond the web experience and also doesn't even know its a local app. (When asked about its capabilities it always responded with reasons pertaining to it being a web app.)

It's available to Pro in the Gemini app (and the gemini.google.com). It isn't available in antigravity. They know that the people who are using these tools for coding are most likely to cough up for the Ultra subscription.

EDIT: Okay, the AI plans page claims under pro - "Expanded access to Gemini 4 Argon in Google Antigravity." So maybe it is just a matter of it rolling out. Though Google has a long history of serious confusing and misinformation on those tier descriptions.

EDIT2: And they changed it again, and now it is explicitly excluded from antigravity for Pro users.