Second Brain Starter

A folder of markdown notes that Claude can read, search, and write back to. Every time you ask it a question about your life and work, it checks the folder first. Every time you tell it something worth remembering, it saves it.

Fifteen minutes to set up. No code.

Quick start

Read SETUP.md and do what it says. It walks you from zero to a working second brain in about 15 minutes. Obsidian, Claude Desktop, this repo, and you are done.

The short version:

1. Install Obsidian and Claude Desktop.
2. Clone this repo, or download and unzip.
3. Open second-brain/ in Obsidian.
4. Open Claude Code in the same folder.
5. Ask Claude anything.

What is CLAUDE.md

Claude Code automatically reads CLAUDE.md at the start of every session. That one file teaches Claude how to navigate your vault: what to read first, where to write new pages, how to keep the index fresh.

Open second-brain/CLAUDE.md to see the full ruleset. It is short, opinionated, and the most important 100 lines in the whole package.

Folder layout

second-brain-starter/
  README.md
  SETUP.md           15-minute setup guide
  second-brain/      the vault skeleton, copy this to your computer
    CLAUDE.md        navigation rules, read by Claude each session
    index.md         the map of every page, kept up to date
    log.md           append-only activity log
    hot-cache.md     last ingest summary, read first
    sources/         raw imports: transcripts, articles, meeting notes
    entities/        people, companies, projects (one page each)
    concepts/        ideas, frameworks, theories (one page each)
    analyses/        your own writeups, decisions, plans, playbooks

Why this exists

I run an AI operations consultancy in Copenhagen. I got tired of re-explaining who I am, who my clients are, and what I am working on every time I opened a new Claude session. So I built a second brain.

Over months it compounded. Now Claude answers questions about my calendar, my open decisions, and my client patterns without me prompting. It remembers what it did yesterday.

I posted about it on Instagram. 200 people asked how. This repo is the how.

Inspired by Andrej Karpathy's LLM Wiki pattern and the Obsidian community's work on agentic note-taking.

Who made this

Nic, solo founder at Cimalys. I ship small AI systems for small businesses.

• Instagram: @nicdoesai
• Website: cimalys.com

License

MIT. Use it, fork it, change it, do whatever you want. Tag me if it works for you.