Term
GRAIN
GRAIN is a retrieval loop: Gather, Rank, Assemble, Inspect, Navigate. Gather collects candidate passages. Rank orders them for the question actually asked. Assemble builds the context the model may see. Inspect checks that the cited chunk is the one used. Navigate decides the next lookup or the refusal. If you cannot point at the passage, you do not have retrieval. You have a fluent guess. The book that owns this name is available now in English and Dutch.
When to use it
Use it when a RAG demo cites the wrong paragraph with a straight face. If the team cannot open the chunk the model used, the loop is broken at Inspect.
Do not confuse with
Not a grain-size metaphor and not “we added a vector store.” GRAIN is the inspectable loop. RAG names the architecture. The RAG Engineer is available now in English and Dutch paperback, hardcover, and Kindle.