"how does Google figure out it happened" - no insider knowledge, but the calls Claw makes are very different than the regular IDE, so the calls and volume alone would be an indicator. Maybe Google has even updated their Antigravity IDEs to just include some other User Agent, that Claw auth does not have.

Everything just guesswork, but I don't think it is too hard to figure out whether it is Antigravity calling the APIs or any Claw.