Add Custom Document to Project Documentation

Add individual custom documents to existing project documentation.

Prerequisites

Before running, verify existing documentation exists:

• Check for ./docs/ folder
• Read ./docs/01-prd.md for project context
• Read ./docs/02-tech-stack.md for technical context

If no existing docs found:

⚠️ No existing documentation found in ./docs/

Please run /project-docs first to generate core documentation,
then use /add-doc to add custom documents.