CLAUDE.md vs DESIGN.md: What to Put in Each for Claude Code

Main difference between CLAUDE.md and DESIGN.md

The main difference between the two files is their functional purpose. CLAUDE.md is the operating manual. It tells Claude how to work on the project. DESIGN.md is design source of truth. It tells Claude what the product should look and feel like.

What to put in CLAUDE.md

This file should contain operational instructions that help Claude work more effectively in your project. For a web or mobile design project, this file features commands, architecture, workflows, coding rules, and verification processes.

While every project is different and it’s impossible to provide one-size-fits-all recommendations, there are still a few sections that every project can benefit from: