Beyond RAG: Why I replaced similarity search with graph traversal for AI agent context

The problem RAG doesn't solve RAG is good for question answering. It's bad for tasks that require knowing dependencies before you act. When an AI coding agent asks "what breaks if I change RunnableSequence?" - RAG retrieves text chunks that mention RunnableSequence. Approximate. Probabilistic. It might miss the 23 modules that directly import it. Same problem in life sciences. A PM asks an agent to draft a payer brief for GLP-1 coverage.