---
title: "GRAIN | Glossary"
description: "GRAIN is a retrieval loop: Gather, Rank, Assemble, Inspect, Navigate. Gather governs the corpus: sources, permissions, and versioning. Rank retrieves…"
image: "https://lenvanderhof.com/photos/len-portrait-1.jpg"
---

Term

# GRAIN

GRAIN is a retrieval loop: Gather, Rank, Assemble, Inspect, Navigate. Gather governs the corpus: sources, permissions, and versioning. Rank retrieves candidate passages and reranks them for the question actually asked. Assemble builds the context the model may see. Inspect traces a wrong answer back to the chunk and retrieval decision behind it. Navigate keeps the index fresh: TTL policy, re-ingest, and change detection. 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.

## Essays on this site

- [Evaluate the reasoning, not the fluency](https://lenvanderhof.com/en/blog/evaluate-reasoning-not-fluency/)
- [What is RAG? Retrieval, then generation](https://lenvanderhof.com/en/blog/what-is-rag/)

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