Brownfield Development FAQ

Quick answers to common questions about brownfield (existing codebase) development in the BMad Method (BMM).

Questions

• Questions
  • What is brownfield vs greenfield?
  • Do I have to run document-project for brownfield?
  • What if I forget to run document-project?
  • Can I use Quick Spec Flow for brownfield projects?
  • What if my existing code doesn’t follow best practices?

What is brownfield vs greenfield?

• Greenfield — New project, starting from scratch, clean slate
• Brownfield — Existing project, working with established codebase and patterns

Do I have to run document-project for brownfield?

Highly recommended, especially if:

• No existing documentation
• Documentation is outdated
• AI agents need context about existing code

You can skip it if you have comprehensive, up-to-date documentation including docs/index.md or will use other tools or techniques to aid in discovery for the agent to build on an existing system.

What if I forget to run document-project?

Don’t worry about it - you can do it at any time. You can even do it during or after a project to help keep docs up to date.

Can I use Quick Spec Flow for brownfield projects?

Yes! Quick Spec Flow works great for brownfield. It will:

• Auto-detect your existing stack
• Analyze brownfield code patterns
• Detect conventions and ask for confirmation
• Generate context-rich tech-spec that respects existing code

Perfect for bug fixes and small features in existing codebases.

What if my existing code doesn’t follow best practices?

Quick Spec Flow detects your conventions and asks: “Should I follow these existing conventions?” You decide:

• Yes → Maintain consistency with current codebase
• No → Establish new standards (document why in tech-spec)

BMM respects your choice — it won’t force modernization, but it will offer it.

Have a question not answered here? Please open an issue or ask in Discord so we can add it!