A Google Cloud search offering over an organization's own enterprise data (external search) that combines prebuilt RAG with semantic discovery capabilities, available within Gemini Enterprise Agent Platform.
In GENAI-L (Domains 2.3 and 2.4) it is the official name for Google Cloud's managed search/RAG offering — the conceptual successor to what used to be called Vertex AI Search. It is used both for search exposed to users and to provide context (grounding) to agents.
Agent Search is a concept that can show up on the exam. Check the full guide to see it in context.