Document combat semantics validator evaluation

docs/internal/dnd.md

@@ -134,6 +134,19 @@ relatedness validators report advisory evidence concerns. The configured order
 is documented in
 [Configuration](../config.md#production-validator-keys-and-default-chains).
 
+The optional `extract/dnd/scene-descriptions/combat_semantics` validator is the
+D&D family's LLM-backed review of only combat versus non-combat classification.
+It selects the shared combat-policy prompt fragment, receives the proposed kind
+and current chunk, and maps its verdict deterministically into producer
+guidance. It does not assess titles, summaries, non-combat subtype, or scene
+boundaries; deferred boundary-coherence review remains separate. It is opt-in;
+[Configuration](../config.md) owns selection and retry/failure behavior.
+
+Before proposing default-chain inclusion, run a deliberate provider evaluation
+against the synthetic corpus and record false acceptance, false rejection,
+producer-correction success, added calls, latency, and token use. Default tests
+remain offline and do not measure provider quality.
+
 Every D&D rejection describes the correction in transcript-grounded domain
 terms, using contextual names, artifact fields, and source segment ranges when
 useful. The guidance must not ask the model to reproduce durable entity IDs,