fix(evals): skip invocations without user events

src/google/adk/evaluation/evaluation_generator.py

@@ -627,7 +627,7 @@ def convert_events_to_eval_invocations(
     for invocation_id, events in events_by_invocation_id.items():
       final_response = None
       final_event = None
-      user_content = Content(parts=[])
+      user_content = None
       invocation_timestamp = 0
       app_details = None
       if (
@@ -663,6 +663,9 @@ def convert_events_to_eval_invocations(
               events_to_add.append(event)
               break
 
+      if user_content is None:
+        continue
+
       invocation_events = [
           InvocationEvent(author=e.author, content=e.content)
           for e in events_to_add

tests/unittests/evaluation/test_evaluation_generator.py

@@ -70,6 +70,23 @@ def test_convert_single_turn_text_only(
     assert invocation.final_response.parts[0].text == "Hi there!"
     assert len(invocation.intermediate_data.invocation_events) == 0
 
+  def test_skips_invocation_without_user_event(
+      self,
+  ):
+    """Tests that agent-only invocations are not converted to eval turns."""
+    events = [
+        _build_event("agent", [types.Part(text="Internal response")], "inv1"),
+        _build_event("user", [types.Part(text="Hello")], "inv2"),
+        _build_event("agent", [types.Part(text="Hi there!")], "inv2"),
+    ]
+
+    invocations = EvaluationGenerator.convert_events_to_eval_invocations(events)
+
+    assert len(invocations) == 1
+    assert invocations[0].invocation_id == "inv2"
+    assert invocations[0].user_content.parts[0].text == "Hello"
+    assert invocations[0].final_response.parts[0].text == "Hi there!"
+
   def test_convert_single_turn_tool_call(
       self,
   ):