Create, amend, or backprop bugs into SPEC.md at repo root. Sole mutator of the project spec. Triggers when the user asks to write a spec, start a new spec, distill a spec from existing code, add invariants, amend sections (§G, §C, §I, §V, §T, §B), or record a bug via backprop. Common phrasings: "wri

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: grill → sharpened §G + §C research → §R rows (add the §R section if absent) review → drafted §V lines + the risk verdict deepen → §I/§V/§T amendments ⊥ rewrite a section the handoff did not name. Sectioned ownership (see FORMAT.md). NEW — idea → spec Input: user idea. If it arrived fuzzy, prefer running grill first. Steps: 1. Extract goal (1 line, caveman). → §G. 2. List constraints user stated or implied. → §C. 3. List external surfaces user named. → §I. 4. §R only if research ran — else omit the section (right size). 5. Propose initial invariants. → §V (numbered V1…). 6. Break goal into ordered tasks. → §T pipe table, all status . , ids T1… 7. §B section with header row only ( id date cause fix ). Write to SPEC.md . Show user full file. Ask: "spec OK? /review if high blast radius, else /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.