CLAUDE.md
A file at the root of your project holding instructions for the agent: rules, commands, conventions. It gets read automatically.
Not the same as documentation
Documentation explains the project to people. This file instructs the agent, and it is read at the start of every session — which is why a rule written here beats the same correction typed for the fourth time.
Where it bites
The test for what belongs in it is simple: if you have said it twice, write it down. Everything else is noise that competes for the same context the actual task needs.
Covered in these lessons
Related terms
Where this comes up
Also written as claude.md, claude-md, agents.md. Checked 2026-08-06.