Google Agentic Architect - Subconcept 2.2: Tool Augmentation & Grounding

Analyze the technical implementation of tool augmentation and grounding within the Gemini and Vertex AI ecosystem. Break down Vertex AI Search managed grounding, focusing on how document ingestion, chunking, and semantic retrieval produce explicit citations ("grounding_chunks") to eliminate model hallucinations. Contrast Native Function Calling (where the application runtime handles tool execution and observation injection) with Vertex AI Extensions (which use hosted OpenAPI specs and manage middleware authentication like OAuth2, API keys, or OIDC). Conclude with a deep dive into Vertex AI Vector Search, explaining how the ScaNN algorithm provides sub-5ms similarity search at billion-vector scale.