A solo builder's honest account of what worked, what failed, and what surprised me after six months of building persistent cognitive memory infrastructure. Building a Personal AI Second Brain: Architecture Decisions That Actually Mattered A solo builder's honest account of what worked, what failed, and what surprised me after six months of building persistent cognitive memory infrastructure. Why I Built This I'm a solution architect and enterprise systems specialist. I spend enormous amounts of time consuming and producing knowledge — and losing most of it. Standard RAG tutorials show you how to answer questions from documents. I wanted something different: a system that compounds in value over time, that strengthens the more you use it, and that maintains reasoning continuity rather than treating every query as a fresh start. Six months in, the results exceeded my expectations. Here's what I actually learned.…