glossary · The ideas behind the fiction

Retrieval-augmented generation: finding a source is one step

By Robert Wescott · Updated November 4, 2026 · Sources checked November 4, 2026

Retrieval-augmented generation, usually called RAG, combines a generative model with a process that retrieves material relevant to a request. Lewis and colleagues' foundational work joins learned model information with an external retrieval mechanism. Read the paper.

A simple way to follow the process is to separate finding material from composing an answer. A service may search a collection, choose passages, and supply those passages to a model. The response can then quote, summarize or draw inferences from them. Those operations deserve different labels.

The policy that really exists

Imagine asking whether a club member was allowed to take equipment home last Tuesday. The archive contains both the rule in force that day and a replacement issued on Wednesday. A search retrieves the replacement because it is prominently labeled current. The generated answer accurately summarizes it.

Nothing in this invented example requires a fabricated document. The failure is the relationship between the question and the evidence selected. The relevant question was historical; the retrieved source described the present.

To check the answer, the reader needs the policy's effective date, the cited passage and enough surrounding text to see any exception. A link to the club's home page would offer less help. So would a precise citation to a document that does not answer the question being asked.

A source can be incomplete

An archive is also a selection. It may contain one person's letters and none of the replies. A generated account can sound balanced while drawing on that uneven collection. Showing sources helps a reader recognize the imbalance; it cannot manufacture the missing record.

That is why “uses your documents” should start a conversation about coverage, dates, permissions and citation quality. It should not end the conversation about accuracy. A system may be useful while still needing to say that the available material does not settle a claim.

Two fictional uses

The Evidence Was Perfect explores a genuine record applied to the wrong question. The Last Person Who Remembers turns to the emotional authority of a reconstructed family account. Both are non-canon stories. Neither describes a real RAG product or demonstrates its failure rate.

For another step, compare content provenance, which concerns a record's history, with AI memory, which separates different ways information can persist. A reader should be able to ask where an answer came from without having to become the system's engineer.

Listen with this question in mind

Sources and limits

The examples and recommendations are editorial explanations. Fiction illustrates the questions; it is not evidence of real-world outcomes.

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