diff --git a/src/agents/openai-transport-stream.ts b/src/agents/openai-transport-stream.ts
index 4a11d00df2a..b13feb5ec8b 100644
--- a/src/agents/openai-transport-stream.ts
+++ b/src/agents/openai-transport-stream.ts
@@ -2219,7 +2219,6 @@ function getCompat(model: OpenAIModeModel): {
     visibleReasoningDetailTypes:
       compat.visibleReasoningDetailTypes ?? detected.visibleReasoningDetailTypes,
     requiresReasoningContentOnAssistantMessages:
-      compat.requiresReasoningContentOnAssistantMessages ??
       detected.requiresReasoningContentOnAssistantMessages,
   };
 }