RAG From First Principles: Why Every AI App Retrieves Before It Generates

Large language models have a problem nobody talks about at the beginning. You train a model on terabytes of internet data. It knows a lot. But it doesn't know your data — your company's policies, your product docs, last week's incident report, or the contract you signed yesterday. Ask it anyway, and it does something worse than saying "I don't know." It makes something up that sounds perfectly correct. This is called hallucination, and it's the reason you can't just point GPT-4 at your enterpr...