CLAUDE .md is the most important file in Claude.

This is exactly how Boris Cherny sets his up:

- CLAUDE .md is one text file. - It sits in your project folder. - Claude reads it before every reply.

Without one, Claude has no idea who you are.

Boris's version is the infographic below. Save it as your starting template.

3 steps to install yours:

1. Create the CLAUDE .md file. 2. Paste in Boris's rules from below. 3. Tell Claude to update it as you work.

It builds itself from there.

tutorial