spec — spec mutator

Read FORMAT.md at repo root if not already loaded. Caveman skill applies to all writes here.

DISPATCH

Inspect user request and project state:

1. No SPEC.md at repo root AND args describe idea → NEW
2. No SPEC.md AND from-code in args → DISTILL
3. SPEC.md exists AND args start bug: → BACKPROP
4. SPEC.md exists AND args start amend → AMEND
5. SPEC.md exists, no args → ask user which mode

INPUTS — spec is the sole mutator

The other verbs produce material; spec writes it. Ingest their handoff blocks into the right section, show a diff, write on OK: