Google's mechanism for deciding, per query, whether Gemini runs a live search — governed by a default grounding threshold of 0.3.
Dynamic retrieval is Google's mechanism for deciding, query by query, whether Gemini should run a live web search before answering or reply from its own trained knowledge. Rather than searching every time, the system scores how much a query would benefit from fresh web content and only grounds when that score clears a threshold.
Google's documented default threshold is 0.3: the point at which a query is judged to deserve grounding. Below it, the model answers from memory; above it, it fetches and cites live pages.
We confirmed this behaviour in a live production environment and built a replica of the decision in our Grounding Classifier. For anyone optimising for AI search, dynamic retrieval is the gate that decides whether a query is even open to your content.
