The Second Brain That Builds

Everyone's building an AI second brain. Most stop at thinking. Mine builds — real apps, agents, and systems — and I'll show you how to build your own.

Andrej Karpathy points an AI at a folder and it writes the whole wiki — reads his sources, builds the pages, links them together, keeps itself current. Nineteen million people watched him describe it. Brian Halligan trained an agent on his entire life and sends it to his meetings. Tiago Forte took the second brain he’s famous for and handed the filing to the machines.

The smartest people in tech are all building the same thing right now: an AI that knows what they know, remembers what they’d forget, and acts on it. I’ve been building mine on Claude Code, Obsidian and Git, and it’s the most useful thing I own.

Most of these systems stop at the same place, though — they think. They remember, they advise, they help you decide. Mine does all that, and then it builds. I point it at a real problem and it makes something that wasn’t there before: an app, an agent that runs on a schedule, a pipeline that mines twenty years of my own files and surfaces what I’d forgotten I knew, infrastructure that runs itself. Every week it gains functionality. Every week it does more of my actual work.

That’s what this is. Second Brain Chronicles is where I build it in the open — the functionality I’m adding, what it’s taking off my plate, and exactly how you build the same.

And you can build one too. Now, not someday. The entry point is lower than it looks: you point a capable model at your files and start giving it jobs. I did it, I’m still doing it, and I’m going to show you every step.

One principle runs through all of it: recognition over recall. The system puts the right thing in front of me at the right moment, so it works on my worst day, not just my best. Build it that way and it holds up under real life.

The gap between the people building these systems and everyone else widens every week. I’d rather you were on the right side of it.

So pull up a chair. Subscribe and build alongside me.

— Jim