Second Brain Template: A Free, AI-Ready Setup in Plain Markdown
Most second brain templates are Notion dashboards that look finished on day one and go quiet by week three. A template that lasts is smaller: four folders, a note template, a source log and a weekly checklist, in plain text your AI tools can read. Here is what goes in one, and a free copy.
Founder of The Viable Edge, with 20+ years of experience helping businesses build competitive advantage through strategic transformation. Expert in AI-era business strategy and systematic implementation.
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A good second brain template is small: four folders (inbox, notes, sources, archive), a one-idea note template, a source log and a 20-minute weekly checklist. Keep it in plain markdown so it works in any app and any AI tool can read it. Our free starter kit is exactly that, seven files you can set up in 30 minutes.
A second brain template is a ready-made structure for keeping your notes outside your head: the folders, the note format and the routine that keeps it current. It saves you designing a system from scratch, so you can start capturing today. The best ones are small enough that you will still use them a month from now.
If the idea of a second brain is new, start with what a second brain is. The short version: it is a place where you write down what is worth remembering, so you can find it again and so an AI can answer from it.
Most templates online are Notion dashboards with dozens of linked databases. They photograph well. The trouble is that every database is something to maintain, and when maintenance slips, the whole thing goes quiet. A template is only as good as the habit it supports.
What should a second brain template include?
Four folders and four working files. The folders are inbox, notes, sources and archive. The files are a capture guide for the inbox, a one-idea note template, a source log that records where each idea came from, and a weekly maintenance checklist. Anything beyond that is optional and can wait until you need it.
Part
What it does
inbox
Catches everything fast, unsorted. Nothing lives here longer than a week.
notes
Processed notes, one idea each, written in your own words.
sources
A running log of where each idea came from, so any claim can be checked.
archive
Finished or outdated material, kept but out of the way.
This is close to the PARA structure from the Building a Second Brain method, cut down to what a beginner uses. You can add projects and areas later, once you know which ones you return to.
Is a Notion template or a plain markdown template better?
For a second brain an AI will read, plain markdown wins. The files open in any editor, sync with any service, and every major AI tool can read them directly without an export. Notion is pleasant for teams already living in it, but your notes then sit in one company's format, and AI access depends on its integrations.
The question is less "which app" and more "who can read this in five years". Markdown files in a folder will open in whatever you use next. Obsidian, VS Code or a plain text editor all work, and so does pointing Claude or ChatGPT at the folder.
The capture inbox, note template, source log, weekly checklist, connect-your-AI guide and retrieval self-test, as plain markdown files that work in Obsidian or any editor, with Claude or any AI. Enter your email and the download starts.
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How do you set up a second brain template?
Pick one synced folder and create the four subfolders. Copy the working files into place. Capture five things you would otherwise forget by tomorrow, without organizing them. Then put a 20-minute weekly block on your calendar to empty the inbox into notes. The whole setup takes about 30 minutes, and the weekly block is what makes it stick.
Pick a location. One folder, synced however you like. Fifteen minutes here beats a month of choosing the perfect app.
Create the folders. inbox, notes, sources, archive.
Add the templates. The capture guide, note template, source log and weekly checklist.
Capture five things now. Rough is fine. Capture first, organize weekly.
Book the weekly pass. Same day, same time, 20 minutes: empty the inbox, log sources, archive what is done.
What does a good second brain note template look like?
One idea per note, titled as the idea itself rather than the topic. Each note carries the date you wrote it, a source line, the idea in two to six sentences in your own words, and links to related notes. That small, consistent shape is what lets you, or an AI, find the right note later and trust it.
# [The idea itself, as a title]
Date: [when you wrote it]
Source: [book, link, conversation, or "original thought"]
## The note
[Two to six sentences, in your own words.]
## Related
- [[another note]]
The test for "one idea" is simple: if you cannot state the note's point in one sentence, split it. Long notes covering several ideas are the main reason searches, and AI answers, land on the wrong passage.
How do you connect a second brain template to AI?
Because the template is plain text, connecting it is mostly pointing your AI tool at the folder. Claude Code, a Claude Project or ChatGPT can all read markdown files. Start with questions you know the answers to, keep private material in a separate folder, and run a ten-question retrieval test once your notes reach a few dozen.
The source line on every note is what makes AI answers checkable. When the model cites a note, you can follow the source back and see whether the claim still holds.
Build and Deliver Professional Second Brains is a self-paced course on doing this for other people: scoping the engagement, building a knowledge base from a client's real material, testing retrieval, and handing it over, with a working knowledge base kit to build with. Plain files, no coding, no vector database.
