The Second Brain System
What this gives you: One place that runs your entire business - Sales, Marketing & Content, Operations & Fulfilment, and Finance & Strategy - instead of fifteen scattered tabs. A free, plug-and-play Obsidian vault wired for Claude Code, so the brain fills itself. This is the exact structure I use to run a six-figure business with a tiny team.
What a second brain actually is
Most business owners run their company across fifteen tabs. The CRM, the docs, the spreadsheets, the chat threads, the notes app nobody opens. The information exists, it is just scattered. So nothing connects, and you end up holding the whole business in your head.
A second brain fixes that. It is one place that pulls every department together, surfaces what matters, and remembers everything so you do not have to. You stop organising tools and start organising information.
It runs on three simple layers:
- Capture - everything lands in one inbox first. Notes, calls, ideas, numbers. Nothing gets lost.
- Organise - each item gets filed into one of four departments and linked so related notes connect.
- Surface - a daily note pulls today's priorities from every department, and you can ask the brain a question and get an answer from your real business.
The whole thing is plain text in Obsidian. You own it forever. No subscription, no lock-in.
The 4 departments
Your business already thinks in departments. The vault mirrors that, so every part has one front door (a Map of Content note that links to everything in that area).
01 - Sales / Pipeline
Leads and where they came from, calls booked and their outcome, follow-ups owed, and the status and next action of every deal in one view.
02 - Marketing & Content
Every idea and hook, scripts in progress, published posts and their angle, and notes on what actually performed.
03 - Operations & Fulfilment
Client and project status, your SOPs (the repeatable way each job gets done), and the handoffs between people and tools. This is how new team members onboard from the brain instead of from your calendar.
04 - Finance & Strategy
The numbers (revenue, margin, cost per lead), the decisions and the reasoning behind them, planning, and hiring. Log the decision, not just the outcome - the reasoning is the asset.
Set it up in about 5 minutes
Step 1 - Get Obsidian
Download it free at obsidian.md. It is a plain-text notes app, and the vault below is just a folder of Markdown files.
Step 2 - Download the Second Brain template
Or download the ZIP from the GitHub repo.
Step 3 - Open it as a vault
In Obsidian, choose Open folder as vault and select the second-brain-starter folder. Open 00 - Home.md - that is your dashboard.
Step 4 - Turn on two plugins
Settings - Community plugins - enable Dataview and Templater. The dashboards use Dataview to list your notes automatically.
Step 5 - Start capturing
Drop anything and everything into 00 Inbox/. File it into a department when you have a minute. Capture fast, file later.
That is it. You now have a working second brain.
Let Claude Code fill it for you
A second brain is good on its own. It gets powerful when something fills it for you. The template ships with a CLAUDE.md kernel so Claude Code knows how your brain is organised.
Once it is set up, you can ask Claude Code to:
- File my inbox - it reads everything in
00 Inbox/, decides which department each note belongs to, moves it, and links it from the right Map of Content. - Write my daily brief - it pulls today's priorities, owed follow-ups, and open decisions from all four departments into one note.
- What is the status of [client or deal] - it answers from your real notes, not the internet.
You capture, Claude Code organises, and the brain compounds. Every day it knows more about your business than the day before.
How to make it grow
- Start with one department. You only need one to feel it work. Most people start too big and stall.
- Write an SOP every time you explain something twice. That is how the business stops living in your head.
- Connect it to Claude Code early. Without AI it is a filing cabinet. With AI it is a brain. Learn the setup in The AI OS Starter.