diff --git a/python/packages/openai/agent_framework_openai/_chat_client.py b/python/packages/openai/agent_framework_openai/_chat_client.py
index 32f5ec0187..9b6f66c633 100644
--- a/python/packages/openai/agent_framework_openai/_chat_client.py
+++ b/python/packages/openai/agent_framework_openai/_chat_client.py
@@ -763,7 +763,7 @@ class RawOpenAIChatClient(  # type: ignore[misc]
         if headers is None:
             return None
         served_model = headers.get(cls.SERVED_MODEL_HEADER)
-        if isinstance(served_model, str):
+        if isinstance(served_model, str) and len(served_model) > 0:
             return served_model
         return None