{
  "fact": {
    "id": "fact_hard_invariants",
    "fact_kind": "skill_capability",
    "title": "Hard invariants (non-negotiable)",
    "description": "ANTHROPIC_API_KEY must never appear in any file (OAuth-only). Conventional Commits with an (O<N>) suffix on every commit. third_party/ is gitignored, never written or scanned. No defensive code at internal boundaries - validate at system edges only. No comments explaining what code does, WHY-only. No half-implementations. api_key_present must be false in every EngineeringFileResult output.",
    "source_doc": "anthropic-skills:engineering-coworker (hard_invariants block)",
    "created_at": "2026-07-02 04:46:31",
    "cite_as": "https://subagentengineering.com/api/engineering-role-facts/fact_hard_invariants"
  }
}