RAG and Vector Databases

RAG, short for Retrieval-Augmented Generation, lets an AI agent pull facts from stored data each time it answers. The data sits in a vector database. In that database, every text chunk is turned into a number list called a vector. Similar ideas create vectors that lie close together, so the agent can find related chunks fast. When the user asks a question, the agent turns the question into its own vector, finds the nearest chunks, and reads them. It then writes a reply that mixes the new prompt with those chunks. Because the data store can hold a lot of past chats, documents, or notes, this process gives the agent a working memory without stuffing everything into the prompt. It lowers token cost, keeps answers on topic, and allows the memory to grow over time.