Start from scratch
The brain starts empty: no template to fill in, nothing to import. You connect an AI, ask it to remember something, and the note appears. From there it grows as you work.
What you need
An account and a connected AI. The rest you do by talking.
- A Cobrain account, free: you sign in with your email.
- An AI connected to the brain. With Claude it is four steps, with Claude Code a single line; the other guides are here.
The steps
Five. Three happen in the chat with your AI, two in the dashboard, to see what it did.
Sign in and look at the empty brain
Go to app.cobrain.space and sign in with your email. On the left is the folder tree: right now it is empty, and that is fine. You do not have to create anything by hand before you start.
Ask your AI to remember something
Open a chat with the AI you connected and tell it something you want to find again in a month. Here is an example to paste, with your own content in place of ours:
Remember that the client ACME pays at 60 days and wants invoices as PDFs. Save it in my brain, under clients/acme.
The AI creates a note in the brain. If you tell it the folder, as here, it uses it; if you do not, it picks one and says which. A folder that does not exist is created along with the note.
Watch it appear
Go back to app.cobrain.space and reload. In the tree there is the folder clients/acme, and the note inside it. Open it: it is Markdown text, and you can fix it from here just as from any editor. Beside it you see who edited it last, and if it was an AI, which one.
Ask another chat for it
Open a new chat, or another AI if you connected two, and ask:
What do you know about the client ACME? Search my brain before answering.
The AI searches the brain, reads the note and answers with the 60 days and the PDF invoices. That is the whole idea: what one chat writes, the others read.
Give your first unit an index card
A unit is something you follow over time: a client, a project, a student. It is a folder with an _about.md file inside: who they are, where things stand, what matters. When you mention ACME, the AI reads the card first and the rest after. Ask it to create one:
Set up ACME as a unit in my brain, of type client, in the folder clients/acme. Then fill in its index card with what you know and ask me for what is missing.
The folder gains _about.md, _ai.md (the rules for any AI working on ACME) and decisions.md (one dated line per decision). They are notes like any other: you open them and change them whenever you want.
How the brain is made
Three things to know, then you can forget about it.
- They are Markdown files in folders. There is no Cobrain format: what you see in the tree is what is there. You export all of it whenever you like and open it with anything.
- The AI appends, it does not rewrite. When you say «add», it puts the text at the end of the note. If it tries to replace a long note with a short text, Cobrain stops it and asks for confirmation.
- The folders are your organisation. One per client, one per project, as you would on your computer. When there are too many to read at once, the AI reads one sub-folder or one tag: the page on context costs explains why that pays.
Already have notes somewhere? The guide Bring in the notes you already have gets your AI to move them across. Want a colleague to read a branch? Sharing a branch.
Ten minutes, and it already has a note.
You sign in with your email, connect an AI, and ask it to remember something. The rest grows as you work.
