Google adds Claude Opus 5.5 and Sonnet 5.5 to Antigravity

The notable signal is competitive rather than technical: Google is listing a rival lab's frontier models inside its own agentic development platform, a posture that treats model access as a distribution play rather than a walled garden. Developers choosing a stack on Antigravity gain another vendor option without leaving Google's tooling, which matters most for teams trying to avoid single-supplier dependence. The absence of pricing, rate limits or regional rollout detail leaves the practical terms unresolved. Whether this becomes a standing multi-vendor lineup or a narrow pilot is the open question.