Decoder. plain-English AI glossary

Non-parametric memory

● Core

Knowledge a model pulls in from outside itself at answer time, rather than from its weights.

Think of it like

Like an open-book exam — the facts live in the book on your desk, not only in your memory.

Example

A RAG system fetches the exact policy paragraph and hands it to the model, so the answer comes from a document, not the weights.

How it actually works

Non-parametric memory keeps knowledge in an external, swappable store — documents, a vector database, a tool — that the model reads on demand. Its advantages are updatability and citation: you can change a fact without retraining, and the model can point to where an answer came from. The cost is a retrieval step that can fail.

For product teams

How you keep answers current and auditable without retraining the whole model.

For engineers

Knowledge held in an external store queried at inference; updatable and attributable, unlike weights.

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