Google Updates Antigravity Agent Preview for Local Tooling
Google released antigravity-preview-09-2026 on September 17, 2026. This update changes local tool parameters to PascalCase and uses line-range file edits.
Release Details and Scope
Google announced the release of antigravity-preview-09-2026 on September 17, 2026. This preview model replaces and deprecates the previous antigravity-preview-05-2026 iteration. The model is part of the Gemini family and supports text input and text output. It features a context window of 1,048,576 tokens and a maximum output of 65,536 tokens. Open weights are not confirmed for this release.
Changes to Local Environment Tools
The update introduces specific changes for users running tools in a local environment or parsing function call steps. Parameters now use PascalCase instead of snake_case. For file editing capabilities, the system uses line-range replacements rather than full rewrites. In contrast, users operating in a remote sandbox who read only output text or model output steps require only an update to the agent string, with no other changes necessary.
- Parameters switched from snake_case to PascalCase.
- File edits utilize line-range replacements instead of full rewrites.
- Remote sandbox users reading output text only need to update the agent string.
Evaluation Procedure for Engineers
Engineers can evaluate the new preview by testing its behavior in both local and remote configurations. First, test the model in a local environment by executing a file creation command using the new PascalCase parameters, such as WriteToFile. Measure the response structure to validate that it returns line-range replacement data rather than full file content. Next, compare the output format against the deprecated 05-2026 version to confirm the structural shift. Finally, validate that remote sandbox executions requiring only output text processing remain functional after updating the agent string. These steps verify the documented interface changes without assuming performance improvements.
Primary sources
Frequently asked questions
Does the new preview support open weights?
The source facts indicate that open weights are not confirmed for antigravity-preview-09-2026. No information is provided regarding local installation requirements or hosting arrangements beyond the API observation.
What must I change if I use a remote sandbox?
If you run on a remote sandbox and read only output text or model output steps, you must update the agent string to antigravity-preview-09-2026. According to the source, nothing else changes for this specific configuration.