Garry Tan manages billions at YC. He still spent his nights coding his own AI memory system, because every agent forgets you the second you close the tab. You explain your situation, get a great answer, come back the next day and explain it from scratch. You're the only one with memory in the relationship. He called it GBrain and open-sourced it for free. It builds a persistent brain on top of your agent from everything you say, save, and think through. Mention someone, their page starts…