CLAUDE.md

Simple Definition

CLAUDE.md is a project instruction file used with Claude Code to store rules, context, coding preferences, and repeated corrections for future AI coding sessions.

Think of it as a memory file for Claude Code that tells the AI how to work inside your project.

Why It Matters

Without project memory, you re-explain the same rules every session. CLAUDE.md lets you write a rule once so future sessions follow it automatically, turning repeated corrections into lasting project knowledge.

Example

If Claude keeps changing global styles by mistake, you add a rule to CLAUDE.md telling it not to edit global CSS unless explicitly asked. Future sessions then respect that rule on their own.

Related Terms

• DESIGN.md, the visual-rules counterpart to CLAUDE.md
• AI Coding Agent, the kind of tool CLAUDE.md guides
• Worktree, isolated workspaces where those project rules apply
• Prompt Engineering, writing clear, reusable instructions
• Context Engineering, giving AI the right project context
• Vibe Coding, building with AI, where saved rules improve results
• Related guide: Setting up Claude Code agents