Spec Driven Development

Before you write a single line of code, this skill makes you write a spec that defines what you're building, why, and how you'll know it's done. It uses a four phase gate (specify, plan, tasks, implement) where you can't move forward until the human approves each stage. The real value is in surfacing assumptions early. It forces you to list what you're assuming about the tech stack, architecture, and requirements before proceeding, which catches misunderstandings when they're cheap to fix instead of after you've written 500 lines in the wrong direction. Skip it for typo fixes, use it when touching multiple files or making architectural calls.