Claude Opus 5.5 and Claude Sonnet 5.5 are now available in Google Antigravity

Google Cloud added Anthropic's Claude Opus 5.5 and Claude Sonnet 5.5 to Google Antigravity for its customers, giving developers a choice of model families inside one agent harness.

• Opus 5.5 is built for complex work, while Sonnet 5.5 is a faster, lower-cost complement, and once an administrator enables them developers pick either from the model picker.
• The models apply across Antigravity 2.0, the Antigravity CLI and the Antigravity IDE extensions for VS Code, JetBrains IntelliJ and Visual Studio, under unified enterprise billing and security.
• Google Cloud says partner models do not draw on the pooled Gemini Enterprise monthly token quota and are billed pay-as-you-go through an existing Google Cloud Billing account, so overages must be enabled.
• Administrators configure overage billing, spend limits and partner model authorization in the Google Cloud Console, or enable Claude models in Model Garden after completing the standard Anthropic terms.