u/alifgokce

The agent forgets the user's allergy from 20 messages ago. Everyone recognizes this one.


The opposite gets less attention: the agent that never forgets. A one-off joke from three months ago keeps resurfacing in unrelated conversations. Retrieval pulls in stale context, and the agent can't focus because its head is full of irrelevant history.


Both are the same root mistake: treating memory as storage instead of as a 
*relevance decision*
. An LLM is stateless — "memory" is just the engineering question "what do I put back into context on the next call?" That makes forgetting a first-class design decision, not a bug: TTLs on episodic memories, confidence decay on facts that haven't been re-confirmed, and explicit contradiction handling when a new fact conflicts with a stored one (the new one should usually win, but silently keeping both is how agents get weird).


The teams I've seen do this well spend more time on eviction and staleness than on retrieval.


How are you deciding what your agents 
forget
?