Python: Fix Chat History Agent format instructions regression.

python/semantic_kernel/agents/chat_completion/chat_completion_agent.py

@@ -123,6 +123,9 @@ async def invoke(
         else:
             arguments.update(kwargs)
 
+        # Add the chat history to the args in the event that it is needed for prompt template configuration
+        arguments["chat_history"] = history
+
         kernel = kernel or self.kernel
         arguments = self.merge_arguments(arguments)
 
@@ -188,6 +191,9 @@ async def invoke_stream(
         else:
             arguments.update(kwargs)
 
+        # Add the chat history to the args in the event that it is needed for prompt template configuration
+        arguments["chat_history"] = history
+
         kernel = kernel or self.kernel
         arguments = self.merge_arguments(arguments)
 
@@ -245,11 +251,13 @@ async def _setup_agent_chat_history(
         self, history: ChatHistory, kernel: "Kernel", arguments: KernelArguments
     ) -> ChatHistory:
         """Setup the agent chat history."""
-        return (
-            ChatHistory(messages=history.messages)
-            if self.instructions is None
-            else ChatHistory(system_message=self.instructions, messages=history.messages)
-        )
+        formatted_instructions = await self.format_instructions(kernel, arguments)
+        messages = []
+        if formatted_instructions:
+            messages.append(ChatMessageContent(role=AuthorRole.SYSTEM, content=formatted_instructions, name=self.name))
+        if history.messages:
+            messages.extend(history.messages)
+        return ChatHistory(messages=messages)
 
     async def _get_chat_completion_service_and_settings(
         self, kernel: "Kernel", arguments: KernelArguments

python/tests/unit/agents/test_chat_completion_agent.py

@@ -1,5 +1,6 @@
 # Copyright (c) Microsoft. All rights reserved.
 
+from collections.abc import AsyncGenerator, Callable
 from unittest.mock import AsyncMock, create_autospec, patch
 
 import pytest
@@ -18,15 +19,13 @@
 
 
 @pytest.fixture
-def mock_streaming_chat_completion_response() -> AsyncMock:
-    """A fixture that returns a mock response for a streaming chat completion response."""
-
+def mock_streaming_chat_completion_response() -> Callable[..., AsyncGenerator[list[ChatMessageContent], None]]:
     async def mock_response(
         chat_history: ChatHistory,
         settings: PromptExecutionSettings,
         kernel: Kernel,
         arguments: KernelArguments,
-    ):
+    ) -> AsyncGenerator[list[ChatMessageContent], None]:
         content1 = ChatMessageContent(role=AuthorRole.SYSTEM, content="Processed Message 1")
         content2 = ChatMessageContent(role=AuthorRole.TOOL, content="Processed Message 2")
         chat_history.messages.append(content1)
@@ -242,3 +241,41 @@ async def test_create_channel():
     channel = await agent.create_channel()
 
     assert isinstance(channel, ChatHistoryChannel)
+
+
+async def test_setup_agent_chat_history_with_formatted_instructions():
+    agent = ChatCompletionAgent(
+        name="TestAgent", id="test_id", description="Test Description", instructions="Test Instructions"
+    )
+    with patch.object(
+        ChatCompletionAgent, "format_instructions", new=AsyncMock(return_value="Formatted instructions for testing")
+    ) as mock_format_instructions:
+        dummy_kernel = create_autospec(Kernel)
+        dummy_args = KernelArguments(param="value")
+        user_message = ChatMessageContent(role=AuthorRole.USER, content="User message")
+        history = ChatHistory(messages=[user_message])
+        result_history = await agent._setup_agent_chat_history(history, dummy_kernel, dummy_args)
+        mock_format_instructions.assert_awaited_once_with(dummy_kernel, dummy_args)
+        assert len(result_history.messages) == 2
+        system_message = result_history.messages[0]
+        assert system_message.role == AuthorRole.SYSTEM
+        assert system_message.content == "Formatted instructions for testing"
+        assert system_message.name == agent.name
+        assert result_history.messages[1] == user_message
+
+
+async def test_setup_agent_chat_history_without_formatted_instructions():
+    agent = ChatCompletionAgent(
+        name="TestAgent", id="test_id", description="Test Description", instructions="Test Instructions"
+    )
+    with patch.object(
+        ChatCompletionAgent, "format_instructions", new=AsyncMock(return_value=None)
+    ) as mock_format_instructions:
+        dummy_kernel = create_autospec(Kernel)
+        dummy_args = KernelArguments(param="value")
+        user_message = ChatMessageContent(role=AuthorRole.USER, content="User message")
+        history = ChatHistory(messages=[user_message])
+        result_history = await agent._setup_agent_chat_history(history, dummy_kernel, dummy_args)
+        mock_format_instructions.assert_awaited_once_with(dummy_kernel, dummy_args)
+        assert len(result_history.messages) == 1
+        assert result_history.messages[0] == user_message