# Build Your Business Brain — Claude Prompts

Ready-to-paste prompts for Claude. Build the Brain once, wire your tools to load it on every session, then keep it current with monthly maintenance.

The Brain is a local folder on your machine. It is read by Claude tools that have filesystem access — **Claude Cowork** (desktop app) and **Claude Code** (CLI). Browser sessions on claude.ai cannot reach your local filesystem. If you need similar functionality there, use a Claude Project with uploaded files — that is a different mechanism, not in scope here.

Source: *Build Your Business Brain — The Operator's Guide*, First Edition, April 2026.
Method credit to [@alex2learn](https://instagram.com/alex2learn) on Instagram.
Companion to the slide deck at https://ai-leonidas.ch/brain.

---

## 1 — Initial build prompt (run once)

Use this the very first time. It tells Claude to read every file in your dump folder, convert each to Markdown, design a structure that fits your business, build it as an Obsidian vault, cross-link related notes, and write a README. Run on Claude Max ($100) for the initial build — you can downgrade afterwards.

Paste this into Claude Code or Cowork — both have filesystem access and can do this work. Plain claude.ai cannot read or write your local folder, so it cannot run this prompt.

```
I have a folder at ~/Desktop/business-brain-raw containing every
document related to my business — SOPs, brand guidelines, customer
notes, contracts, transcripts, everything.

I want you to:

1. Read through every file in that folder.
2. Convert each one into a clean Markdown (.md) file.
3. Design an organizational structure specific to my business and
   the way I work with you and sub-agents on projects.
4. Build that structure as an Obsidian vault at
   ~/Desktop/business-brain.
5. Cross-link related notes so I can navigate from one to the next.
6. At the end, write me a short README explaining the structure
   you chose and how I should reference the Brain in future
   projects.

Don't ask permission for each file. Just go.
```

---

## 2 — Wire up Cowork and Claude Code (run once)

After the Brain is built, wire both tools so the Brain is loaded automatically on every session. After this step, you do not type "reference the Brain" any more — Cowork and Claude Code do it for you. You just describe what you need.

### Claude Cowork (desktop app)

Open Cowork → **Settings → Cowork → Instructions**. Paste this block:

```
Before responding, read the README at ~/Desktop/business-brain.
Pull whatever's relevant from the Brain for the user's task.

Voice and rules live in the Brain (00-overview/voice-and-tone.md,
00-overview/what-we-do.md). NDA material stays offline, never in
the Brain.

Keep the Brain current. When facts change (new customers, new
processes, new automations), update the relevant overview note.
When the user mentions a new task, add it to 00-overview/todo.md.

Capture drive-by ideas. Any suggestion you make during the
conversation that the user does not act on, append it to
00-overview/ideas.md before the conversation ends. Otherwise it
gets lost.
```

From the next Cowork chat onwards, Cowork pulls from the Brain on its own.

### Claude Code (CLI)

Create a file named `CLAUDE.md` at the root of your Brain folder, with the same content as the Cowork block above. Claude Code reads `CLAUDE.md` automatically on every session started in that directory.

```
~/Desktop/business-brain/
├── CLAUDE.md             ← loaded automatically by Claude Code
├── README.md
├── 00-overview/
├── 01-operations/
└── …
```

For a setup that works in **every** Claude Code session regardless of directory, place the same file at `~/.claude/CLAUDE.md` instead.

### Where this works and where it does not

| Tool | Filesystem access | Wiring works? |
|---|---|---|
| Claude Cowork (desktop) | yes | yes |
| Claude Code (CLI) | yes | yes |
| claude.ai (browser) | no | no — use a Claude Project instead |
| Generic API call | depends on your code | only if you implement file access |

The Brain in this guide is a local folder. It is invisible to anything that cannot read your filesystem.

---

## 3 — Day-to-day: just describe the task

Once wired, every Cowork chat and every Claude Code session in your Brain directory already knows the Brain. You skip the project-opener step entirely. Describe what you need.

### Examples

**Marketing campaign**

```
Drei Q2-Kampagnenideen, im Stil unserer letzten Briefings.
Voice und ICP findest du im Brain.
```

**Sales proposal**

```
Angebot über $40k für [client name]. Vorlage und Preise liegen
im Brain.
```

**Hiring**

```
Stellenausschreibung Customer Success, passend zu unserem Setup.
SOPs, Voice und Kundengespräche im Brain.
```

The "im Brain" hint is optional. Claude already knows the Brain is loaded — the hint just nudges Claude toward the right corner of it. Drop it once you trust the wiring.

---

## 4 — Monthly maintenance (run once a month)

A Brain that never updates rots. Drop new files into a `_inbox` subfolder throughout the month, then run this once a month so Claude files them into the existing structure.

```
Take everything new in ~/Desktop/business-brain-raw/_inbox and
add it to the Business Brain following the existing structure.
If anything doesn't fit, propose a new folder rather than dumping
in 99-archive.
```

---

## 5 — Quarterly audit (run once a quarter)

Every three months, ask Claude to look at the whole Brain with fresh eyes and propose restructures.

```
Audit the Business Brain at ~/Desktop/business-brain. Look at
which folders have grown, which are empty, which notes are
duplicated, and where the cross-linking has broken down. Propose
restructures where the current shape no longer matches how my
business actually works. Don't make changes yet — just propose.
```

---

## Setup checklist

- [ ] Upgrade to Claude Pro ($20) or Max ($100). Max strongly recommended for the initial build.
- [ ] Install Obsidian (free) from https://obsidian.md.
- [ ] Block 3–5 uninterrupted hours on your calendar.
- [ ] Create a folder on your Desktop called `business-brain-raw`.
- [ ] Collect every relevant document into it (PDFs, DOCX, Notion exports, transcripts, screenshots — anything with text).
- [ ] **Don't organize, rename, or sort.** Claude will design the structure.
- [ ] Open Claude Code or Cowork. Paste prompt #1.
- [ ] Walk through the resulting Obsidian vault. Iterate once if anything doesn't match how you actually work.
- [ ] **Wire Cowork and Claude Code (prompt #2)** so the Brain is referenced automatically from now on.
- [ ] Drop new files into `_inbox` throughout the month, run prompt #4 monthly, prompt #5 quarterly.

---

Build it once. Reference it forever.

Need help with the setup? https://ai-leonidas.ch/#kontakt