Every time you start Claude Code, it forgets who you are. Fresh conversation, no memory of what you discussed yesterday, no idea what your project is about or how you like things done.
Unless you leave it a note.
CLAUDE.md is a text file you put in your project folder. Claude Code reads it automatically at the start of every conversation. It's like a sticky note on the fridge: "This is the project, this is what matters, this is what NOT to do."
One file. Permanent memory. Every session starts informed instead of clueless.
I use this myself on every project I work on. My CLAUDE.md files typically include the tech stack, folder structure, coding standards, and things I want Claude to remember or avoid. This article will show you how to build your own.