Requirements — Part 3: Prioritizing with MoSCoW

maang.io AI-Native Builder Series

📦 Artifacts for this topic — build against these, and check your own with them:
reference → artifacts/reference/streakup-requirements.md (the filled-in requirements + MoSCoW table) ·
prompt → artifacts/prompts/01-draft-and-critique-moscow (have the AI critique your split) ·
check your work → artifacts/verify.md.
Build yours first, then compare — the reference is a mentor's version to verify
against, not an answer key to paste.

What is this?

Imagine you're packing a single backpack for a week-long trip, and your stuff is in four piles by the door. Pile one: things you literally cannot go without — passport, phone, charger, meds. If even one is missing, you don't leave. Pile two: things you really want and will pack if there's room — a good jacket, a second pair of shoes. Pile three: things that'd be nice if there's space left over — a book, a camera. Pile four: things you've decided, on purpose, to leave home this time — the guitar, the third pair of jeans, the "just in case" gadgets. The backpack only holds so much. The whole art of packing is sorting your stuff into those four piles and being honest about which is which.

That's exactly what prioritizing requirements is. You've got a list of everything StreakUp could do (Part 1) and a rough sense of what's in and out (Part 2). Now you give that sorting a real method — one that working teams use every day — so your decisions are clear, defensible, and shareable. The backpack is your summer; the four piles have names; and the method is called MoSCoW.

The one-line idea: sort every feature into Must / Should / Could / Won't, and the line between "Must" and everything else is your MVP.

This is the last chapter of the Requirements topic, and by its end you'll have the finished requirements piece of your Spec Package — a prioritized list that tells you, and your team, and the AI, exactly what to build first.