Vertex AI Search offers multiple model versions for you to choose whengenerating answers. You can choose the model versions when usingsearchsummaries andanswers andfollow-ups.

Available models

Vertex AI Search uses two types of models for question and answeringuse cases:

• Vertex AI LLM models that have been tested on question andanswering tasks
• Vertex AI Search models that are based on Vertex AI LLMmodels and further trained to address question and answering tasks

Vertex AI Search models share the same discontinuation date as theirbase Vertex AI LLM models. The base LLM model is available for sixmonths after the release date of the next version of the model, per theVertexAI model lifecyclepolicy.Leave enough time to migrate to new models before the discontinuation dates.

The following table lists model version specifications. When you set a modelspecification, the API uses the specified model to generate answers.