diff --git a/agent/chat_completion_helpers.py b/agent/chat_completion_helpers.py
index 7a5e7534723..ace3b6439de 100644
--- a/agent/chat_completion_helpers.py
+++ b/agent/chat_completion_helpers.py
@@ -2086,7 +2086,7 @@ def interruptible_streaming_api_call(agent, api_kwargs: dict, *, on_first_delta=
                             entry["function"]["arguments"] += tc_delta.function.arguments
                     extra = getattr(tc_delta, "extra_content", None)
                     if extra is None and hasattr(tc_delta, "model_extra"):
-                        extra = (tc_delta.model_extra or {}).get("extra_content")
+                        extra = (tc_delta.model_extra if isinstance(tc_delta.model_extra, dict) else {}).get("extra_content")
                     if extra is not None:
                         if hasattr(extra, "model_dump"):
                             extra = extra.model_dump()
diff --git a/agent/transports/chat_completions.py b/agent/transports/chat_completions.py
index 42e81dc30e7..878045da66d 100644
--- a/agent/transports/chat_completions.py
+++ b/agent/transports/chat_completions.py
@@ -619,7 +619,7 @@ class ChatCompletionsTransport(ProviderTransport):
                 tc_provider_data: dict[str, Any] = {}
                 extra = getattr(tc, "extra_content", None)
                 if extra is None and hasattr(tc, "model_extra"):
-                    extra = (tc.model_extra or {}).get("extra_content")
+                    extra = (tc.model_extra if isinstance(tc.model_extra, dict) else {}).get("extra_content")
                 if extra is not None:
                     if hasattr(extra, "model_dump"):
                         try: