Clarify encoder and MoE output contracts

README.md

@@ -79,7 +79,7 @@ Example normalized JSON output:
 }
 ```
 
-The encoder does not output generated answers, explanations, citations, source spans, retrieval results, or experimental multitask-head fields.
+The encoder does not output generated answers, explanations, citations, source spans, retrieval results, taxonomy/category tags, route IDs, scalar diagnostics, or experimental multitask-head fields. Taxonomy/category fields that appear in evaluation reports are benchmark metadata used for breakdowns; route, taxonomy, and scalar heads are part of the experimental MoE track, not the published nano encoder output contract.
 
 ## Intended Use