Antigravity's model picker gains two Claude models, letting developers switch mid-thread without losing workspace state
Synopsis
Google Antigravity's model picker now includes Claude Opus 5.5 and Claude Sonnet 5.5 for Google Cloud customers, selectable by developers once an administrator enables them. Previously the models available inside Antigravity came from Google's own Gemini line, including Gemini 3.8 Flash and Gemini 4 Argon; Opus 5.5 targets complex work while Sonnet 5.5 is a faster, lower-cost complement. Both apply across Antigravity 2.0, the Antigravity CLI and the IDE extensions for VS Code, JetBrains IntelliJ and Visual Studio, and the active model can be switched between turns in one conversation thread while preserving workspace state, open artifacts and terminal context.
Interpretation
Antigravity's model picker adds Claude Opus 5.5 and Claude Sonnet 5.5, which Google Cloud customers can select directly in the tool once an administrator enables them. Before this, the models selectable in Antigravity were Google's Gemini models, including Gemini 3.8 Flash and Gemini 4 Argon. The two Claude models appear alongside the Gemini models in the same model picker, under a unified enterprise billing and security boundary.
The two models split by task: Opus 5.5 is built for complex work, and Sonnet 5.5 is a faster, lower-cost complement. When a single model family both writes and reviews code, it can reinforce that model's own blind spots. Availability covers Antigravity 2.0, the Antigravity CLI, and the Antigravity IDE extensions for VS Code, JetBrains IntelliJ and Visual Studio.
Developers can switch the active model between turns in the same conversation thread, keeping workspace state, open artifacts and terminal context. Multi-model workflows previously meant carrying context between separate tools or sessions. Administrators configure pay-as-you-go billing and spend limits and authorize partner models in the Gemini for business console, or enable Claude models in Model Garden on the Gemini platform and complete the standard Anthropic terms.
Perspective
The report covers the product availability information published by Google Cloud: Claude Opus 5.5 and Sonnet 5.5 are in the Antigravity model picker, cover Antigravity 2.0, the Antigravity CLI and three IDE extensions, and can be switched within one conversation thread while preserving workspace state. The two engineering patterns are aimed at developers building agentic loops and multi-step graph workflows in Antigravity. Administrators must first enable pay-as-you-go billing and spend limits and authorize partner models in the Gemini for business console, or enable Claude models in Model Garden on the Gemini platform and complete the Anthropic terms.
The announcement gives no quantitative comparison of cross-model verification or reasoning-plus-Flash delegation on code quality, latency or cost. Partner models do not draw from the pooled Gemini Enterprise Standard and Plus monthly token quota; they are billed pay-as-you-go through the existing Google Cloud Billing account, so overages must be enabled. Lightweight first-party Gemini models still run in the background for high-frequency client-side coordination such as context management and summaries, consuming first-party tokens that can incur charges.