Antigravity Agent 09-2026

The Gemini API's antigravity-preview-09-2026 replaces and deprecates antigravity-preview-05-2026. If you use a remote sandbox and only read output_text or model_output steps, you can switch the agent string without other changes.

If you run tools locally or parse function_call steps, you'll need to update your integration. Built-in tool parameters now use PascalCase instead of snake_case, and file edits use line-range replacements instead of full rewrites. File reading also moves from byte offsets to line ranges, with dedicated tools for file and code search.

The Antigravity documentation has the replacement tool signatures.