How to Build a 'Second Brain' Using AI

Based on the approach proposed by Andrej Karpathy, this explains how to build a personal knowledge base using only folders and text files, without any separate software or database.

The core is creating a three-folder structure.

• raw/: A place to hold all unprocessed source material, such as articles, notes, and screenshots
• wiki/: A systematic wiki space organized and written by AI
• outputs/: A place where AI-generated answers, reports, and research outputs are stored

To automate data collection, you can use Vercel Labs' agent-browser CLI tool. This tool helps an AI agent control an actual browser to scrape JavaScript-based sites or pages hidden behind logins, and save them directly to the raw/ folder.

The core of the system is the Schema file (e.g., CLAUDE.md). By defining the purpose of the knowledge base and the organizing rules in this file, the AI can update and manage the wiki on its own based on the raw data, creating a structure that gets smarter the more it is used.