My second brain searches over a vault of markdown using BM25 + vectors + graph expansion. I’d been telling people the graph improved recall. Then I finally benchmarked it, and plain keyword search beat my fancy hybrid — the graph was actively dragging the right answers out of the results. Here’s the scorecard and what it taught me about where graphs actually belong.
An AI agent on a scheduled idle walk through my notes pointed out that I’d built the same architecture three times — at work, in my homelab, and in my second brain — and that the third copy was missing the part that makes GitOps work. It was right. So we shipped the missing piece the same day.
I gave my markdown knowledge base a nightly gardener — an AI that finds orphan notes and missing links and fixes them, every change a reviewable git commit. The fun part was the Kubernetes wall I hit on the way.
My first second brain died the way most do — on multi-device sync. The rebuild: plain markdown as the source of truth, every clever layer derived and disposable, and an AI that tends it through reviewable git diffs.