Last updated: 2026-05-11
RAG vs Agent Memory
RAG grounds an answer in external knowledge; agent memory changes how future runs behave for a user or task.
Quick recommendation: Choose RAG for document grounding. Choose agent memory when the product must remember user or task facts over time. Use both only after the boundary is explicit.
Choose the first option when
- You need answers grounded in a corpus.
- Permissions are document or record based.
- You can evaluate retrieved chunks directly.
Choose the second option when
- The agent must learn durable user preferences.
- Task context spans many sessions.
- Users need to inspect and correct what the agent remembers.
Feature comparison
| Primary job | Find relevant external knowledge | Persist useful facts for future behavior |
|---|---|---|
| Failure mode | Wrong or missing evidence | Stale, unsafe, or over-personalized memory |
| Best first metric | Retrieval precision and answer groundedness | Future-task improvement and correction rate |
Developer experience
RAG is easier to test because evidence can be inspected per query. Memory requires retention policy, user controls, and regression tests over time.
Final recommendation
Start with RAG if the question is about knowledge. Add memory only when remembering changes the product outcome.