Gemini API releases antigravity-preview-09-2026 managed agent to replace the 05-2026 version

Archive entry: this covers an event from September 17, 2026, and we published it on November 8, 2026. The details come from sources dated at the time and may have changed since.

On September 17, 2026, the Gemini API released antigravity-preview-09-2026, a managed agent version meant to replace antigravity-preview-05-2026, as announced in the Gemini API changelog. The version introduced six tools for working with files and searching and switched tool parameters to PascalCase.

What changed in the managed agent

• Tool parameters switched to PascalCase, and file edits were specified with line ranges.
• The version added six tools: write_to_file, replace_file_content, view_file, list_dir, find_by_name and grep_search.
• The code_execution and google_search tools were unchanged from the earlier version.
• Remote-sandbox users who read only output_text needed only a model-string change to move to the replacement.
• The older version, antigravity-preview-05-2026, was set to shut down on October 5, 2026.

What it means for people who build with AI

For developers who build on Google's hosted coding agent through the API, this was a breaking change. Integrations that depended on the agent's tool parameters or file edits had to be adapted to PascalCase parameters and line-range edits before the older version was set to shut down on October 5, 2026. The code_execution and google_search tools were unchanged, and remote-sandbox integrations that read only output_text were the simplest case, since they needed only the replacement model string.

Sources

• Gemini API changelog: September 17, 2026 (Google AI Studio (Gemini API changelog), September 17, 2026, official)

Written with AI assistance, strictly from the sources listed above. Before it went live, automated checks verified its dates, sources and every language edition.