The first wall companies hit when adopting generative AI is realizing "ChatGPT doesn't know our internal documents." Large language models (LLMs) train on public data up to a cutoff date only—yesterday's internal wiki or confidential contracts are invisible to them. Two paths exist: (1) retrain the model on our data (fine-tuning), or (2) every time we query, retrieve relevant documents and tell the model "answer based on these documents." The latter is RAG (Retrieval Augmented Generation) and is the standard architecture for nearly all internal knowledge chatbots