Distinguish Gemini 2.5 Pro's preview from its stable release
The June 2025 preview preceded the stable model, so the version name matters when comparing behavior.
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Google introduced an upgraded Gemini 2.5 Pro preview in June 2025, with access through the Gemini API in Google AI Studio and Vertex AI. The announcement also described thinking budgets for controlling cost and latency [1].
A preview is not the stable endpoint
Our social caption combined the words preview and stable. Google's later model-family announcement identified stable versions of Gemini 2.5 Pro and Flash separately [2]. Keep those release stages distinct when reading older tutorials or reproducing a result.
A model family name does not identify every dated preview within that family. If an example names a particular endpoint, record that exact identifier before comparing outputs.
Record the conditions of a test
For your own evaluation, keep the model identifier, settings, prompt and expected result together. If you change the thinking budget, compare both answer quality and response cost on the same task.
Those checks are more informative than assuming that a later release behaves identically because its name still contains 2.5 Pro.
This article explains the 2025 release sequence. Consult current model availability and deprecation documentation before building around an old preview identifier.
Keep this guide
Filed under AI agents
Sources
- Google: upgraded Gemini 2.5 Pro previewblog.google
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