Guides / CLAUDE.md explained

CLAUDE.md explained for people who don't code

Stignova · 19 October 2026 · 8 min read · template included

What it is, in plain words

Think of it as the note you would leave a new assistant on their first day: who the clients are, how you like emails written, what never to do. The difference is that Claude reads this note again at the start of every session, so it never forgets it.

The .md ending means Markdown, a simple way of writing text where # starts a heading and - starts a list item. Any text editor can open it, including Notepad on Windows and TextEdit on a Mac.

Where it goes, and where it works

• In your work folder: a CLAUDE.md in the folder you open in Claude applies to everything you do there.
• For all your folders: a CLAUDE.md in the .claude folder in your user folder applies everywhere. Good for personal preferences such as language and tone.
• In a subfolder: a CLAUDE.md inside, say, Clients/Lumen/ is read when Claude starts working in that subfolder. Good for one client's specifics.

This is how Claude Code works, according to Anthropic's documentation, and that includes the Code tab of the Claude desktop app. Cowork, the desktop app's mode for everyday work, has its own global instructions in Settings; whether it also reads a CLAUDE.md inside a project folder is something we are still confirming.

What to put in it

1. Who you are and what you do, in two or three lines.
2. How you want Claude to work: language, tone, length, format.
3. Your rules: what to always do and what never to do, each as one short sentence.
4. Pointers to other files for the details, so the main file stays short.

What to leave out

• Long background. Anthropic recommends staying under about 200 lines per file. Longer files take up more of Claude's attention and make the rules less likely to be followed.
• Contradictions. If one line says "keep emails short" and another says "always explain in detail", Claude may follow either one.
• Facts that change often. Prices and client status belong in a separate file, so updating them never touches your rules.
• Passwords and other secrets. The file is read in full every session.

A template for a freelancer

Copy this into a file named CLAUDE.md in your work folder and replace the examples with your own.

# CLAUDE.md

I am Mila, a freelance brand designer. I work alone,
mostly for small companies in food and hospitality.

Facts that are true now (clients, prices, status):

@MEMORY.md

## How to write to me
- Answer in English, short and plain.
- Give the answer first, then the reason.
- When there is a choice, recommend one option and say why.

## How to write to my clients
- Calm, friendly, no exclamation marks.
- Sign emails "Mila".
- Never promise a date I have not confirmed.

## Rules
- Quotes always include two revision rounds and 50% upfront.
- Before you say something about a client, check it in MEMORY.md.
- If you are not sure, say so. Do not guess.

## Where things are
- Clients/ has one file per client: brief, contacts, history.
- rates.md has my prices.
- ARCHIVE.md has old prices and finished projects.

The line @MEMORY.md tells Claude to read that file too, at the start, as if it were written into this one. Keep the facts that change there, and your rules here. Imported files count toward the same attention budget, so they should stay short as well.

A rule is a strong hint, not a lock

Anthropic is clear that Claude treats CLAUDE.md as context, not as enforced settings. Specific, short, consistent rules are followed much more reliably than long or vague ones, but nothing in the file can force Claude. For the few things that must never happen, there are separate technical safeguards; for everything else, a well-kept file is enough.

Keep it alive

• When you correct Claude twice for the same thing, that correction belongs in the file.
• When a fact stops being true, move it to ARCHIVE.md instead of leaving it next to today's facts.
• Once a month, read it top to bottom and delete what no longer applies.