Google Cloud customers can now pick Claude Opus 5.5 and Sonnet 5.5 in Antigravity, billed per token

Announced Oct 20, admins opt in from the Cloud Console and usage is billed pay-as-you-go outside the pooled Gemini Enterprise quota, with both models at four thinking levels across Antigravity 2.0, the CLI (agy --model claude-opus-5-5-medium), and the VS Code, JetBrains, and Visual Studio extensions. Background Gemini models still handle context management and summaries, so those tokens can add charges too (docs).