Composer (Cmd+I) is Cursor's most powerful feature — it can write, edit, and create multiple files simultaneously to implement entire features from a single prompt.

What Composer Can Do

• Create new files from scratch
• Edit multiple existing files in one operation
• Build entire features end to end
• Implement a spec or requirements document

How to Use

1. Press Cmd+I to open Composer
2. Describe what you want to build in detail
3. Composer shows a plan and proposed file changes
4. Review the diff for each file
5. Accept all changes or cherry-pick what you want

Reference:

Cursor Composer documentation

https://docs.cursor.com/composer/overview