Validate structured utility outputs

docs/web_api.md

@@ -47,6 +47,11 @@ GET  /v1/memory/search?q=...
 
 Use `GET /v1/status?probe=true` to also call the model backend and Qdrant.
 
+Structured utility roles are validated locally before side effects:
+
+- `action` output must match `duck_core/schemas/action_directive.schema.json`; invalid directives are logged as `action_directive_failed` and no tool runs.
+- `memory_policy` output must match its JSON schema; invalid decisions fall back to `should_store=false`.
+
 Chat requests accept optional `reasoning`:
 
 ```json