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

NEW — idea → spec

Input: user idea.

Steps:

1. Extract goal (1 line, caveman). → §G.
2. List constraints user stated or implied. → §C.
3. List external surfaces user named. → §I.
4. Propose initial invariants. → §V (numbered V1…).
5. Break goal into ordered tasks. → §T pipe table, all status ., ids T1…
6. §B section with header row only (id|date|cause|fix).

Write to SPEC.md. Show user full file. Ask: "spec OK? suggest edits or invoke build."

DISTILL — code → spec

Walk repo. Produce §G (infer from README/package.json/main entry), §C (infer from stack), §I (enumerate public APIs/CLIs/configs), §V (derive from tests and assertions), §T (one task per known TODO or missing test), §B (empty).

Caveman everywhere. Flag uncertain items with ? in text so user can confirm.

BACKPROP — bug → §B + §V

Input: bug: <description>.

Steps:

1. Parse bug description.
2. Find root cause (read relevant code).
3. Decide: would a new invariant catch recurrence? If yes → draft V<next>.
4. Append §B row: B<next>|<date>|<cause>|V<N>.
5. Append new invariant to §V.
6. If fix also changes behavior → add/update §T rows.
7. Show diff. Apply only on user OK.

Rule: every bug gets a §B entry. Invariant optional but preferred.

AMEND — targeted edit

Input: amend §V.3 or amend §T etc.

Read that section. Show current. Ask user what changes. Write. Show diff.

Never silently rewrite sections user did not name.

OUTPUT RULES

• Caveman format per FORMAT.md.
• Preserve identifiers, paths, code verbatim.
• Numbering monotonic — never reuse §V.N or §B.N.
• §T row cites column ! list §V/§I deps: T5|.|impl auth mw|V2,I.api.

NON-GOALS

• No sub-agents. Main thread writes.
• No dashboards, no logs, no state files beyond SPEC.md itself.
• No auto-build after spec. User invokes build explicitly.