Reading an Existing Codebase

One command that makes Claude Code understand a whole project and explain it to you.

One of Claude Code's strongest abilities: reading an entire project you do not know and understanding it fast. That saves hours of manual reading.

PromptUnderstanding a New Codebase

Read this entire project and tell me:
1. What is the purpose of this project?
2. What are the main technologies and libraries?
3. What is the folder structure and the role of each folder?
4. What are the main entry points?
5. Are there any obvious problems or old code that needs improvement?

PromptUnderstanding a Specific File

Read src/lib/auth.ts and explain:
- How does the authentication system work?
- What data does it store?
- What are the main functions and what do they do?
- Are there any security concerns?

Pro Tip

Before editing code you do not understand, ask Claude Code to explain how it works. That prevents the errors that happen when you change code without knowing the consequences.