Core Brainstorm

It stops Claude from jumping straight to code and forces an actual conversation about the problem first. The prompting is sharp: it tells Claude to act like a cofounder who pushes back, not an assistant who agrees with everything. You get short responses, hard questions, and a structured brief at the end that feeds directly into planning. The brief format alone (problem statement, decisions, open questions, constraints) is worth stealing even if you don't use the mode. Best for when you know something needs to be built but you're not sure what shape it should take yet.