The flash models, for coding are reckless in my experience. I have a Ultimate subscription, get good quota, but still use Opus 4.6 as it's much more reliable if you manage the context window carefully.
That said, I do trust Opus and Fable enough to let them deploy to staging. Great for debugging. Just don't give them keys for prod
My experience is that antigravity is awful and reckless - but that the model itself isn't.