I manage my business with a small fleet of AI agents now, and the hardest problem I've hit is not getting them to reason well. It's getting them to remember the right things, for the right amount of time, and to forget the rest. I learned this the slow way, by building my own memory system twice. I Built This Twice, and the First Version Failed for a Boring Reason The first version was what I'd now call an agent-brain: a folder of notes the agents could read and write, organized by project (my take on the Karpathy LLM Wiki). It worked for about a month. Then it started contradicting itself. A decision I'd reversed in August was still sitting next to the reversal in September, and the agent had no way to know which one was current. Nothing was wrong with the notes. What was missing was a layer above them that tracked state: what's an action in progress, what's a decision that's final, what's a fact that just needs distilling later. That gap is why I ...