Part 3A: Enterprise RAG Architecture & Codebase Vector Indexing

Answer-first: Enterprise code Retrieval-Augmented Generation transcends naive line-based text chunking by combining Tree-sitter Abstract Syntax Tree parsing, hybrid BM25 and dense vector search, and GraphRAG symbol knowledge graphs, enabling autonomous engineering agents to resolve multi-hop inter-service dependencies, navigate deep interface inheritance hierarchies, and eliminate hallucinated method signatures across massive distributed code repositories. Prerequisite: Understanding of vector databases, lexical search (BM25), code syntax trees, and knowledge graph representations. 1. The Fallacy of “Plug-and-Play” Vector Search When engineering teams attempt to index large repositories using generic RAG tools, developers quickly encounter the “Garbage-In, Garbage-Out” paradox: ...