Agent skill · software engineering · juliusbrussee
spec
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: "write the spec for...", "new spec", "bug: ...", "amend §V.3", "distill spec from code", "spec this idea". Reads and follows FORMAT.md for the caveman encoding rules and pipe-table shape of §T and §B.
Why this skill is useful
Adds a comprehensive automation script for managing project specifications, including bug tracking and distillation from code, which fundamentally enhances the AI's capability to maintain project documentation.
What it needs
Requires git installed locally. About 2k tokens when loaded. Last updated 2026-06-18. 1,134 stars on the source repository.
What this skill does
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. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills juliusbrussee/spec