Software factory

Solution Gate decides what deserves implementation. Review Gate decides whether a finished diff is correct. This skill owns the span between them: it moves proof inside implementation instead of collecting it afterwards.

accepted shape or Formula
  → 1. implement   → diff
  → 2. reduce      → complexity evidence
  → 3. harden      → failure-path evidence
  → 4. strengthen  → surviving-mutant evidence
  → 5. prove       → observed behavior
→ Review Gate

It is a protocol, not a runtime. Any control plane may execute it. Bind nothing to a specific provider, harness, or model.

0. Decide whether this fires

Run it when a change is accepted, touches more than one behavior, and a single agent would otherwise write, clean, test, and judge it in one context.