Set up your first brain file.
Train your AI once, then stop repeating yourself.

One file the AI reads first.

Every serious AI tool can read a file before it does anything. Claude Code reads a file named CLAUDE.md in your project folder. Other tools have a custom instructions box or a project file. The name does not matter. What matters is that it is one place, in plain language, that says who you are and how you work.

Without it, the AI is a very smart stranger. With it, the AI is a new hire who read the handbook before day one. The difference shows up in the first ten minutes of every session.

Four sections do most of the work.

1. Who we are.

   The business in five lines: what you sell, to whom, in what medium, where, and the names of the companies and people that come up daily. Facts only.

2. How we talk.

   Your voice rules. Short sentences. Words you use and words you never use. Whether you write lowercase. One or two example paragraphs in your real voice.

3. What never changes.

   The rules the AI must not break: things it must never claim, names it must never publish, numbers it may only use once verified, formats you require.

4. What we are working on.

   The current priorities, dated. Three to five lines. This is the part you update every week, and the part that keeps the AI from working on last month's plan.

Keep it under two pages. A brain file that tries to hold everything gets ignored the same way a forty-page handbook does.

Let the AI interview you.

Do not write the file from a blank page. Use the prompt below. It makes the AI ask you the questions a good new hire would ask, then drafts the file from your answers. You edit, you do not author.

• Read it out loud once. If a line sounds like a brochure, cut it.
• Put the date on the priorities section and change it when they change.
• Keep private facts out of any file that could be shared. The brain file is for what the AI needs, not everything you know.

The file is only as good as its last update.

Once a week, spend five minutes: update the priorities, add any rule you found yourself repeating, delete anything the AI no longer needs. When the AI gets something wrong that it should have known, the fix goes in the file, not in the chat.

Rough out the four sections.

Bullet points are fine. The prompt turns them into the file. Entries stay on this page and are not sent anywhere.

Have the AI build it with you.

Paste this into your AI tool. Answer its questions in plain language. Edit what comes back.

You are helping me write a brain file: one plain text document you will read at the start of every session so you stop guessing about my business.

Interview me first. Ask one question at a time, in this order, and wait for my answer before the next:
1. What does the business sell, to whom, and in what medium (face to face, phone, online)?
2. Which company names, product names and people come up every day?
3. How do I write? Ask for two examples of things I have actually written.
4. What must you never claim, never publish, or never do?
5. What are the three to five priorities this month?

Then draft the file with four sections: Who we are, How we talk, What never changes, What we are working on (dated). Under two pages. Plain language. No marketing tone. Mark anything you inferred rather than heard with [confirm].

One prompt. Paste it into Claude. It builds the whole thing for your business.

The Pro pack is a build prompt with blanks for your context: your product, your medium, your team. Fill them in, answer its questions, and it produces the complete system in your words. The PDF explains the method so you can judge the output. The complete brain file template filled in for a real example company, the interview prompts that draft each section, the decisions log, the voice guide, and the setup for every major AI tool.