Google Boosts Gemini Agent Performance with New Harness
Google has released an updated harness for its Gemini managed agents, which run on the company's Gemini 3.8 Flash model. The new antigravity-preview-09-2026 harness uses 40% fewer output tokens on file changes and delivers up to 6% higher task completion on multi-turn software engineering and research tasks.
The Files API allows users to upload data into a running sandbox, list created files, and download individual files or directories. The Credentials API enables secure connection to services like GitHub (NASDAQ:MSFT) and Slack without exposing actual tokens to the model, with credentials stored encrypted and swapped in only at the egress proxy for approved destinations.
The antigravity-preview-09-2026 harness is available in GoogleAIStudio and the Interactions API, with pricing unchanged from the previous version. Google stated that antigravity-preview-05-2026 will be deprecated on October 5, 2026, after which requests will redirect to the updated harness.