Harmondale
Definition

Retrieval-augmented generation (RAG)

Retrieval-augmented generation, or RAG, is a pattern where a system retrieves relevant source material before asking a model to generate an answer. The model is still generative, but the answer is grounded in selected documents, records, or knowledge-base passages.

Last updated: 25 June 2026

Why it matters

RAG can reduce hallucination and make AI useful on private knowledge, but only if retrieval quality is measured.

Signals to watch

  • Source passages are retrieved
  • Answers cite or use documents
  • Bad retrieval causes bad answers