fix: guard None refusal in ItemHelpers.extract_last_content

src/agents/items.py

@@ -691,7 +691,11 @@ def extract_last_content(cls, message: TResponseOutputItem) -> str:
             # ``extract_text`` below.
             return last_content.text or ""
         elif isinstance(last_content, ResponseOutputRefusal):
-            return last_content.refusal
+            # ``last_content.refusal`` is typed as ``str`` per the Responses API schema,
+            # but provider gateways (e.g. LiteLLM) have been observed surfacing ``None``
+            # for typed-str fields (same rationale as the ``ResponseOutputText.text``
+            # guard above).
+            return last_content.refusal or ""
         else:
             raise ModelBehaviorError(f"Unexpected content type: {type(last_content)}")
 

tests/utils/test_pretty_print_and_items.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from openai.types.responses import ResponseOutputMessage, ResponseOutputText
+from openai.types.responses import ResponseOutputMessage, ResponseOutputRefusal, ResponseOutputText
 
 from agents import Agent
 from agents.exceptions import RunErrorDetails
@@ -62,6 +62,32 @@ def test_extract_last_content_returns_text_normally():
     assert ItemHelpers.extract_last_content(msg) == "hello"
 
 
+def _make_refusal_message(refusal: str | None) -> ResponseOutputMessage:
+    return ResponseOutputMessage.model_construct(
+        id="msg_refusal",
+        role="assistant",
+        status="completed",
+        content=[ResponseOutputRefusal.model_construct(type="refusal", refusal=refusal)],
+    )
+
+
+def test_extract_last_content_returns_empty_string_for_none_refusal():
+    """extract_last_content is declared ``-> str`` and must not return None even if
+    the underlying ResponseOutputRefusal.refusal is None.  The same provider
+    gateways (e.g. LiteLLM) that surface ``None`` for ResponseOutputText.text
+    can also surface ``None`` for ResponseOutputRefusal.refusal; the ``or ""``
+    guard must be applied consistently to both branches."""
+    msg = _make_refusal_message(None)
+    result = ItemHelpers.extract_last_content(msg)
+    assert isinstance(result, str)
+    assert result == ""
+
+
+def test_extract_last_content_returns_refusal_normally():
+    msg = _make_refusal_message("I cannot do that")
+    assert ItemHelpers.extract_last_content(msg) == "I cannot do that"
+
+
 def _make_run_error_details(n_input: int = 0, n_output: int = 0) -> RunErrorDetails:
     return RunErrorDetails(
         input="hi",