While working with AI Agents, there is a popular saying: "Never trust one model to behave exactly like another".

This is my saying. It's not popular yet, but now it's destined to be.

On October 20, 2026, Google retires Gemini 2.5 Pro, 2.5 Flash, and 2.5 Flash-Lite. Salesforce documents the change in the Winter '27 release notes: requests to those models get rerouted automatically.

You should pay attention if you're using:

  • Agentforce agents or subagents with an Agent Script model_config pointing to one of the older Gemini 2.5 models.
  • Prompt Builder templates using Gemini 2.5.
  • Custom solutions using the Models API with Gemini 2.5.

If your org just runs the Salesforce Default model option for Agentforce, you're out of scope. This is about the places where somebody explicitly chose Gemini.

So if you're using any of these models, test your prompts and Agentforce behavior against the replacement models before the reroute. And if the results disappoint you – choose your own target instead of inheriting the default one.

For agents specifically, Salesforce calls out GPT 4.1, Claude Haiku 4.5 and Gemini 3.5 Flash as the models it has "thoroughly" tested.

Agentforce Developers Architects Winter '27