Enforce explicit responsibility attribution

- document responsibility attribution as a project-wide invariant
- prevent inferred ownership in protocol rendering
- add negative gold regression for false responsibility assignment
- document future responsibility evidence and attribution model
- record the real-life benchmark finding

AGENTS.md

@@ -70,6 +70,24 @@ Status:
   of the source transcript or consolidated meeting knowledge unless an explicit
   output language is requested.
 
+## Responsibility Attribution Invariant
+
+A person, team or department may be recorded as responsible only when the
+meeting evidence explicitly assigns, accepts or confirms that responsibility.
+
+Discussion, expertise, objection, suggestion, thematic proximity, speaker
+adjacency, organizational assumptions, likely job roles or mere mention do not
+establish ownership.
+
+When support is incomplete or ambiguous, leave the responsible person unset,
+mark the item as unclear where the current schema supports it, and preserve the
+supporting evidence. Never guess.
+
+This invariant applies to extraction, canonicalization, semantic consolidation,
+Canonical Meeting Knowledge, Working Protocol / Arbeitsprotokoll, Distribution
+Protocol / Verteilerprotokoll and Knowledge Objects /
+Wissensdatenbankeintrag.
+
 ## Prompt Engineering Rules
 
 The Gold Standard corpus is the reference specification. Follow Rules 1-11 from