JohnSang16/second-brain-guide on GitHub.

building a second brain with obsidian and claude code

Most “second brain” setups are a pretty notion template with color-coded tags. This is a different approach: an Obsidian vault wired into Claude Code so it doesn’t just store notes, it reads them, remembers you, and works inside them.

why bother

A second brain that only stores things is a filing cabinet with better branding. The point isn’t having more notes, it’s not having to re-explain your situation to an AI every single session. A standing context file, a real folder structure, and an agent that actually reads both before it talks to you turns your notes into something that compounds instead of just piling up.

why it matters as a student

A semester means juggling classes, projects, club work, and internship applications at the same time, and re-explaining your own situation constantly: to a professor, to a recruiter, to yourself three weeks later trying to remember what you already decided. A second brain that actually remembers what you’re applying to, what you already tried, and what a professor already told you cuts that re-orienting tax, so more of the time goes to the actual classwork and applications instead of reconstructing context.

what’s actually in it

• a single file the agent has to read before it says a word to you, standing context on who you are and what you’re working on, not just a note
• real memory across sessions, so it can write down what you’ve corrected it on and what you’re building, and start every conversation sharper than the last
• “skills,” automated capabilities like a daily brief, coaching modes, and a vault-maintenance sweep, that trigger on their own when relevant
• standalone agents for things like research or job scouting that run independently and report results back
• a real folder structure and sync strategy across devices, not just a flat pile of notes

how to actually set it up

Start by having the agent interview you about your goals and current situation, then let it propose a folder structure based on that, rather than starting from a generic template. The system centers on one context file that defines who you are, and everything else (skills, agents, automated filing) builds on top of it.