Enable correction-aware foundational D&D producers

docs/internal/dnd.md

@@ -42,6 +42,13 @@ unknown fields, while preserving semantic candidates for deterministic
 validation. Do not promote a private response envelope into a durable schema;
 the contracts above define durable data.
 
+A D&D producer that declares `single_response_v1` forwards any supplied
+semantic correction to its structured completion and returns an owned copy of
+that completion's exact validated raw response as its model candidate. It does
+not serialize normalized artifacts to create that candidate, so deterministic
+identity, evidence, warning, and durable-schema behavior remains separate from
+the model transport material.
+
 ## Prompt Construction
 
 D&D LLM-facing content lives beneath `assets/dnd/`. Each module contributes a