Programming Tutorials

  Building a RAG (Retrieval-Augmented Generation) pipeline using Vertex AI Agent Builder (formerly Gen App Builder) promises rapid deployment. However, the abstraction layer often hides critical failures. A common scenario for engineers is the "Infinite Spinner" of death during document ingestion, or worse, an agent that refuses to answer questions clearly defined in the uploaded FAQs. This post dissects the architecture of the underlying Discovery Engine to explain why these failures occur and provides production-grade Python solutions to fix ingestion stalls and hallucination issues caused by poor chunking. The Problem: Ingestion Hangs and Retrieval Misses Two distinct but related issues frequently plague production deployments: The Zombie Index:  You upload a batch of PDFs or a URL sitemap. The status indicator remains on "Importing" or "Indexing" indefinitely (4+ hours for small datasets). The Chunking Gap:  You have an FAQ document. A user asks a ques...