CLAUDE.md vs Global Instructions: They Are Not the Same Thing

CLAUDE.md and global instructions are not the same thing. And confusing them will mess up your entire setup.

People dump everything into one or the other and then wonder why their finance project keeps talking like their marketing project. (It's because you told it to. You just don't remember doing it.)

Here's the 30-second version:

The Difference in One Breath

CLAUDE.md lives inside one project folder. It only applies to that project. Your marketing project has one. Your finance project has another. They're separate brains.

Global instructions apply everywhere. Every chat, every project, every Cowork session. Think of global instructions as your permanent identity: your name, your communication style, your time zone. Things that never change no matter what you're working on.

The Right Setup

Put the universal stuff in global instructions. Put the project-specific stuff in CLAUDE.md. You set global instructions in Cowork's settings. You edit CLAUDE.md right in the workspace folder.

Global instructions are who you are. CLAUDE.md is what you're working on.

Use both. That's the whole trick.

This is part 3 of the 20-part Cowork series. All 20 concepts live in the full guide.

Go check yours right now. If your global instructions mention a specific client, you've found your problem.