Memory is not a single feature. It is a set of data and product decisions: what context should persist, who may access it, how long it remains useful, and when retrieval is safer than recall.
Keep request context small
Short-lived context works well for a focused task. It limits accidental carryover and makes behavior easier to reproduce. Longer-running experiences need explicit session and retention choices rather than an ever-growing prompt.
Use knowledge for durable facts
Documents, policies, and reference material belong in managed collections where ownership and updates are visible. Retrieval can then supply current context without turning conversational memory into an unofficial source of truth.
A good memory design explains both what the system remembers and why it is allowed to remember it.