I Gave Claude Cowork an Obsidian Second Brain. Here Is What It Remembered After 11 Sessions

In Part 1, I built a persistent memory system for my AI workflow using Obsidian, a custom MCP server, and Claude Opus 4.6 in Cowork. The system had 16 MCP tools, a structured vault with frontmatter metadata, Dataview queries for structured retrieval, and a context budget of 5 MCP calls at session start. It worked in the controlled environment of a single build session.That is the easy part.Thanks for reading! Subscribe for free to receive new posts and support my work.The hard question was always whether it would stay useful when real work started piling in. When sessions got messy. When I was focused on deadlines instead of metadata hygiene. When the vault grew from 7 seed notes to something larger.So I used it. The Substack project had been running for 5 sessions before I built the second brain. Over the next 11 sessions (sessions 6 through 16), I drafted articles, debugged tooling, generated images, and reorganized content. I did not treat it gently. I treated it the way you treat…