spec

Writes, revises, reviews, and splits a design spec, the document that states what a capability must do (intent, use cases, and checkable criteria on the outcome) before or alongside its code, and derives tests from one. Use when asked to spec a feature, write, revise, or backfill the spec for X, split a spec, judge whether a spec is ready, or turn a spec into tests, even if they only say "is this spec good" or "review the spec". Not for a node of a first-generation SDD project spec under .agents/specs/ that carries a .feature suite (the sdd plugin's start-mission).