Claude Opus 5.5 and Sonnet 5.5 arrive in Google Antigravity

Anthropic's Claude Opus 5.5 and Sonnet 5.5 are now available in Google Antigravity across the 2.0 desktop app, CLI and IDE extensions for VS Code, JetBrains and Visual Studio. Opus 5.5 targets heavy multi-file refactoring and planning, while Sonnet 5.5 is a fast, lower-cost option for everyday coding, with mid-session model switching that preserves context.

• Opus 5.5 targets heavy refactoring and multi-turn planning
• Sonnet 5.5 is a fast, lower-cost model for daily coding
• Models can be switched mid-session via /model without losing context
• Unified billing through Google Cloud with sandbox and MCP policies