Developing
The release notes are dated entries; each is small, but together they describe how Google is packaging agents for businesses.
In 60 seconds
- Gemini 3.8 Flash was made available on September 2, 2026 and became the default model in Gemini Enterprise on September 23, in global, US and EU regions.
- Workflow Builder, formerly Agent Designer, became generally available on September 3 with multi-step automation.
- New observability views show latency and error rates for agents; admins can transfer ownership of shared agents.
- A pay-as-you-go edition and AI developer tools reached invoiced Cloud Billing accounts on September 10.
Impact Layer
- What changed
- Google moved Gemini Enterprise toward a standard model, builder tools and admin controls for running agents.
- Why it matters
- Companies buying agents need monitoring, ownership and billing controls, which are the items in this month's notes.
- Who is affected
- IT and marketing operations teams on Google Cloud and Workspace, and agencies building agents.
- Martech stack area
- Marketing Automation, AI
- Stack impact
- Check which model your agents now use by default and test them before relying on the new default.
- Business impact
- Low Only the release notes were read; features and limits are described in one line each.
- Related technologies
- Related vendors
- What to watch
- Pricing of the pay-as-you-go edition, and adoption of the connector and agent import features.
Google Cloud’s release notes for Gemini Enterprise list these September 2026 changes.
Dated entries
- September 1. Overage controls available to all invoiced Cloud Billing account holders.
- September 2. Gemini 3.8 Flash available in global, US and EU regions.
- September 3. Workflow Builder (formerly Agent Designer) generally available, with multi-step automation. New observability views show latency and error rates for agents.
- September 4. The Monday federated data store reaches general availability and a projects feature launches for building knowledge bases.
- September 10. A pay-as-you-go edition and AI developer tools available to all invoiced Cloud Billing accounts.
- September 21. Administrators can transfer ownership of shared agents.
- September 23. Gemini 3.8 Flash becomes the default model, generally available in global, US and EU regions.
Our read
None of this is a headline feature, and that is the point. The month’s entries are about running agents: who owns them, how they perform, what they cost and which model they use. A default model change can alter outputs without anyone editing an agent, so test your agents after September 23 and record which model each uses. We read only the release notes.
Sources
- Google Cloud: Gemini Enterprise release notes (opens in a new tab)
Source of every dated entry in this article.