diff --git a/python/packages/core/agent_framework/openai/_responses_client.py b/python/packages/core/agent_framework/openai/_responses_client.py
index cdc6103636..2ee8b17a36 100644
--- a/python/packages/core/agent_framework/openai/_responses_client.py
+++ b/python/packages/core/agent_framework/openai/_responses_client.py
@@ -678,8 +678,7 @@ class RawOpenAIResponsesClient(  # type: ignore[misc]
             if last_assistant_idx >= 0:
                 # Collect system/developer messages from before the last assistant
                 system_messages = [
-                    msg for msg in chat_messages[:last_assistant_idx]
-                    if msg.role in ("system", "developer")
+                    msg for msg in chat_messages[:last_assistant_idx] if msg.role in ("system", "developer")
                 ]
                 # Get all messages after the last assistant (new user messages)
                 new_messages = chat_messages[last_assistant_idx + 1 :]
diff --git a/python/packages/core/tests/openai/test_openai_responses_client.py b/python/packages/core/tests/openai/test_openai_responses_client.py
index d902bfeeac..952dbbbcc8 100644
--- a/python/packages/core/tests/openai/test_openai_responses_client.py
+++ b/python/packages/core/tests/openai/test_openai_responses_client.py
@@ -2108,7 +2108,7 @@ async def test_conversation_id_precedence_kwargs_over_options() -> None:
 async def test_message_filtering_with_previous_response_id() -> None:
     """Test that assistant messages are filtered when using previous_response_id."""
     client = OpenAIResponsesClient(model_id="test-model", api_key="test-key")
-    
+
     # Create a multi-turn conversation with history
     messages = [
         ChatMessage(role="system", text="You are a helpful assistant"),
@@ -2116,13 +2116,13 @@ async def test_message_filtering_with_previous_response_id() -> None:
         ChatMessage(role="assistant", text="Nice to meet you, Alice!"),
         ChatMessage(role="user", text="What's my name?"),
     ]
-    
+
     # When using previous_response_id, assistant messages should be filtered but system messages preserved
     options = await client._prepare_options(
-        messages, 
+        messages,
         {"conversation_id": "resp_12345"},  # Using resp_ prefix
     )  # type: ignore
-    
+
     # Should include: system message + last user message
     assert "input" in options
     input_messages = options["input"]
@@ -2130,7 +2130,7 @@ async def test_message_filtering_with_previous_response_id() -> None:
     assert input_messages[0]["role"] == "system"
     assert input_messages[1]["role"] == "user"
     assert "What's my name?" in str(input_messages[1])
-    
+
     # Verify previous_response_id is set
     assert options["previous_response_id"] == "resp_12345"
 
@@ -2138,7 +2138,7 @@ async def test_message_filtering_with_previous_response_id() -> None:
 async def test_message_filtering_without_previous_response_id() -> None:
     """Test that all messages are included when NOT using previous_response_id."""
     client = OpenAIResponsesClient(model_id="test-model", api_key="test-key")
-    
+
     # Same conversation as above
     messages = [
         ChatMessage(role="system", text="You are a helpful assistant"),
@@ -2146,16 +2146,16 @@ async def test_message_filtering_without_previous_response_id() -> None:
         ChatMessage(role="assistant", text="Nice to meet you, Alice!"),
         ChatMessage(role="user", text="What's my name?"),
     ]
-    
+
     # Without conversation_id, all messages should be included
     options = await client._prepare_options(messages, {})  # type: ignore
-    
+
     # Should include all messages
     assert "input" in options
     input_messages = options["input"]
     # System (1) + User (1) + Assistant (1) + User (1) = 4 messages
     assert len(input_messages) == 4
-    
+
     # Verify previous_response_id is NOT set
     assert "previous_response_id" not in options
 
@@ -2163,25 +2163,25 @@ async def test_message_filtering_without_previous_response_id() -> None:
 async def test_message_filtering_with_conv_prefix() -> None:
     """Test that messages are NOT filtered when using conv_ prefix (conversation ID)."""
     client = OpenAIResponsesClient(model_id="test-model", api_key="test-key")
-    
+
     messages = [
         ChatMessage(role="system", text="You are a helpful assistant"),
         ChatMessage(role="user", text="My name is Alice"),
         ChatMessage(role="assistant", text="Nice to meet you, Alice!"),
         ChatMessage(role="user", text="What's my name?"),
     ]
-    
+
     # When using conv_ prefix, should use conversation parameter, not previous_response_id
     options = await client._prepare_options(
         messages,
         {"conversation_id": "conv_abc123"},  # Using conv_ prefix
     )  # type: ignore
-    
+
     # All messages should be included (no filtering for conversation IDs)
     assert "input" in options
     input_messages = options["input"]
     assert len(input_messages) == 4
-    
+
     # Verify conversation is set, not previous_response_id
     assert options.get("conversation") == "conv_abc123"
     assert "previous_response_id" not in options