I used to think the important part of agent memory was logging the decision. August 2026, we shipped B and killed A. That felt like leaving a trail.
It is only half a trail. Three months later the outcome was Y. Looking back, the bet on X was only half right, and Z is what actually moved the needle. Decision, outcome, feedback. Without the last two pieces, you have a history file, not experience.
I see the same pattern in notes that only grow. CLAUDE.md gets another rule every week. Nobody deletes the ones that stopped being true because the team changed, the client changed, or I changed my mind. The agent keeps following dead instructions with full confidence.
If the file only gets longer and never shorter, the feedback loop is dead. Memory that cannot be overturned is just a diary with better formatting.