Plan Feature — Scaffold (internal)

Turn a designed feature into the project's complete planning artifact set, ready for phase-by-phase execution. Fills only the SPEC's engineering half — the product half (goal, context, scope, capability closure) already exists and is marked designed before this skill ever runs (plan-feature's redirect gate guarantees it). Docs only — never code.

When to use

• The plan-feature router calls this once a feature's product half is designed — from design-feature, plan-feature-from-issue, or an already-scoped slug/SPEC — to fill the engineering half of its docs/features/<NN>-<slug>/SPEC.md and the rest of the folder, then update the roadmap.

Not for product definition (that is design-feature) or writing code (that is execute-phase) or deciding whether to build (that is the plan-feature router / triage-issue).