feat: make system_message as optional (#1038)

Author: Wendong-Fan

camel/agents/chat_agent.py

@@ -115,7 +115,8 @@ class ChatAgent(BaseAgent):
     r"""Class for managing conversations of CAMEL Chat Agents.
 
     Args:
-        system_message (BaseMessage): The system message for the chat agent.
+        system_message (BaseMessage, optional): The system message for the
+            chat agent.
         model (BaseModelBackend, optional): The model backend to use for
             generating responses. (default: :obj:`OpenAIModel` with
             `GPT_4O_MINI`)
@@ -144,7 +145,7 @@ class ChatAgent(BaseAgent):
 
     def __init__(
         self,
-        system_message: BaseMessage,
+        system_message: Optional[BaseMessage] = None,
         model: Optional[BaseModelBackend] = None,
         memory: Optional[AgentMemory] = None,
         message_window_size: Optional[int] = None,
@@ -154,10 +155,14 @@ def __init__(
         external_tools: Optional[List[FunctionTool]] = None,
         response_terminators: Optional[List[ResponseTerminator]] = None,
     ) -> None:
-        self.orig_sys_message: BaseMessage = system_message
-        self.system_message = system_message
-        self.role_name: str = system_message.role_name
-        self.role_type: RoleType = system_message.role_type
+        self.orig_sys_message: Optional[BaseMessage] = system_message
+        self._system_message: Optional[BaseMessage] = system_message
+        self.role_name: str = (
+            getattr(system_message, 'role_name', None) or "assistant"
+        )
+        self.role_type: RoleType = (
+            getattr(system_message, 'role_type', None) or RoleType.ASSISTANT
+        )
         self.model_backend: BaseModelBackend = (
             model
             if model is not None
@@ -272,11 +277,12 @@ def reset(self):
             terminator.reset()
 
     @property
-    def system_message(self) -> BaseMessage:
+    def system_message(self) -> Optional[BaseMessage]:
         r"""The getter method for the property :obj:`system_message`.
 
         Returns:
-            BaseMessage: The system message of this agent.
+            Optional[BaseMessage]: The system message of this agent if set,
+                else :obj:`None`.
         """
         return self._system_message
 
@@ -327,12 +333,22 @@ def set_output_language(self, output_language: str) -> BaseMessage:
             BaseMessage: The updated system message object.
         """
         self.output_language = output_language
-        content = self.orig_sys_message.content + (
+        language_prompt = (
             "\nRegardless of the input language, "
             f"you must output text in {output_language}."
         )
-        self.system_message = self.system_message.create_new_instance(content)
-        return self.system_message
+        if self.orig_sys_message is not None:
+            content = self.orig_sys_message.content + language_prompt
+            self._system_message = self.orig_sys_message.create_new_instance(
+                content
+            )
+            return self._system_message
+        else:
+            self._system_message = BaseMessage.make_assistant_message(
+                role_name="Assistant",
+                content=language_prompt,
+            )
+            return self._system_message
 
     def get_info(
         self,
@@ -377,12 +393,15 @@ def init_messages(self) -> None:
         r"""Initializes the stored messages list with the initial system
         message.
         """
-        system_record = MemoryRecord(
-            message=self.system_message,
-            role_at_backend=OpenAIBackendRole.SYSTEM,
-        )
-        self.memory.clear()
-        self.memory.write_record(system_record)
+        if self.orig_sys_message is not None:
+            system_record = MemoryRecord(
+                message=self.orig_sys_message,
+                role_at_backend=OpenAIBackendRole.SYSTEM,
+            )
+            self.memory.clear()
+            self.memory.write_record(system_record)
+        else:
+            self.memory.clear()
 
     def record_message(self, message: BaseMessage) -> None:
         r"""Records the externally provided message into the agent memory as if

camel/societies/babyagi_playing.py

@@ -106,7 +106,7 @@ def __init__(
         )
 
         self.assistant_agent: ChatAgent
-        self.assistant_sys_msg: BaseMessage
+        self.assistant_sys_msg: Optional[BaseMessage]
         self.task_creation_agent: TaskCreationAgent
         self.task_prioritization_agent: TaskPrioritizationAgent
         self.init_agents(
@@ -202,7 +202,8 @@ def init_agents(
 
         self.task_creation_agent = TaskCreationAgent(
             objective=self.specified_task_prompt,
-            role_name=self.assistant_sys_msg.role_name,
+            role_name=getattr(self.assistant_sys_msg, 'role_name', None)
+            or "assistant",
             output_language=output_language,
             message_window_size=message_window_size,
             **(task_creation_agent_kwargs or {}),
@@ -238,7 +239,9 @@ def step(self) -> ChatAgentResponse:
 
         task_name = self.subtasks.popleft()
         assistant_msg_msg = BaseMessage.make_user_message(
-            role_name=self.assistant_sys_msg.role_name, content=f"{task_name}"
+            role_name=getattr(self.assistant_sys_msg, 'role_name', None)
+            or "assistant",
+            content=f"{task_name}",
         )
 
         assistant_response = self.assistant_agent.step(assistant_msg_msg)

camel/societies/role_playing.py

@@ -149,8 +149,8 @@ def __init__(
 
         self.assistant_agent: ChatAgent
         self.user_agent: ChatAgent
-        self.assistant_sys_msg: BaseMessage
-        self.user_sys_msg: BaseMessage
+        self.assistant_sys_msg: Optional[BaseMessage]
+        self.user_sys_msg: Optional[BaseMessage]
         self._init_agents(
             init_assistant_sys_msg,
             init_user_sys_msg,
@@ -454,9 +454,11 @@ def init_chat(self, init_msg_content: Optional[str] = None) -> BaseMessage:
         )
         if init_msg_content is None:
             init_msg_content = default_init_msg_content
+
         # Initialize a message sent by the assistant
         init_msg = BaseMessage.make_assistant_message(
-            role_name=self.assistant_sys_msg.role_name,
+            role_name=getattr(self.assistant_sys_msg, 'role_name', None)
+            or "assistant",
             content=init_msg_content,
         )
 

test/agents/test_chat_agent.py

@@ -69,55 +69,77 @@ def test_chat_agent(model):
         dict(assistant_role="doctor"),
         role_tuple=("doctor", RoleType.ASSISTANT),
     )
-    assistant = ChatAgent(system_msg, model=model)
+    assistant_with_sys_msg = ChatAgent(system_msg, model=model)
+    assistant_without_sys_msg = ChatAgent(model=model)
 
-    assert str(assistant) == (
+    assert str(assistant_with_sys_msg) == (
         "ChatAgent(doctor, " f"RoleType.ASSISTANT, {ModelType.GPT_4O_MINI})"
     )
+    assert str(assistant_without_sys_msg) == (
+        "ChatAgent(assistant, " f"RoleType.ASSISTANT, {ModelType.GPT_4O_MINI})"
+    )
+
+    for assistant in [assistant_with_sys_msg, assistant_without_sys_msg]:
+        assistant.reset()
 
-    assistant.reset()
     user_msg = BaseMessage(
         role_name="Patient",
         role_type=RoleType.USER,
         meta_dict=dict(),
         content="Hello!",
     )
-    assistant_response = assistant.step(user_msg)
 
-    assert isinstance(assistant_response.msgs, list)
-    assert len(assistant_response.msgs) > 0
-    assert isinstance(assistant_response.terminated, bool)
-    assert assistant_response.terminated is False
-    assert isinstance(assistant_response.info, dict)
-    assert assistant_response.info['id'] is not None
+    for assistant in [assistant_with_sys_msg, assistant_without_sys_msg]:
+        response = assistant.step(user_msg)
+        assert isinstance(response.msgs, list)
+        assert len(response.msgs) > 0
+        assert isinstance(response.terminated, bool)
+        assert response.terminated is False
+        assert isinstance(response.info, dict)
+        assert response.info['id'] is not None
 
 
+@pytest.mark.model_backend
 def test_chat_agent_stored_messages():
     system_msg = BaseMessage(
         role_name="assistant",
         role_type=RoleType.ASSISTANT,
         meta_dict=None,
         content="You are a help assistant.",
     )
-    assistant = ChatAgent(system_msg)
+
+    assistant_with_sys_msg = ChatAgent(system_msg)
+    assistant_without_sys_msg = ChatAgent()
 
     expected_context = [system_msg.to_openai_system_message()]
-    context, _ = assistant.memory.get_context()
-    assert context == expected_context
+
+    context_with_sys_msg, _ = assistant_with_sys_msg.memory.get_context()
+    assert context_with_sys_msg == expected_context
+    context_without_sys_msg, _ = assistant_without_sys_msg.memory.get_context()
+    assert context_without_sys_msg == []
 
     user_msg = BaseMessage(
         role_name="User",
         role_type=RoleType.USER,
         meta_dict=dict(),
         content="Tell me a joke.",
     )
-    assistant.update_memory(user_msg, OpenAIBackendRole.USER)
-    expected_context = [
+
+    for assistant in [assistant_with_sys_msg, assistant_without_sys_msg]:
+        assistant.update_memory(user_msg, OpenAIBackendRole.USER)
+
+    expected_context_with_sys_msg = [
         system_msg.to_openai_system_message(),
         user_msg.to_openai_user_message(),
     ]
-    context, _ = assistant.memory.get_context()
-    assert context == expected_context
+    expected_context_without_sys_msg = [
+        user_msg.to_openai_user_message(),
+    ]
+
+    context_with_sys_msg, _ = assistant_with_sys_msg.memory.get_context()
+    assert context_with_sys_msg == expected_context_with_sys_msg
+    context_without_sys_msg, _ = assistant_without_sys_msg.memory.get_context()
+    assert context_without_sys_msg == expected_context_without_sys_msg
 
 
 @pytest.mark.model_backend
@@ -273,17 +295,27 @@ def test_chat_agent_multiple_return_messages(n):
         meta_dict=None,
         content="You are a helpful assistant.",
     )
-    assistant = ChatAgent(system_msg, model=model)
-    assistant.reset()
+    assistant_with_sys_msg = ChatAgent(system_msg, model=model)
+    assistant_without_sys_msg = ChatAgent(model=model)
+
+    assistant_with_sys_msg.reset()
+    assistant_without_sys_msg.reset()
+
     user_msg = BaseMessage(
         role_name="User",
         role_type=RoleType.USER,
         meta_dict=dict(),
         content="Tell me a joke.",
     )
-    assistant_response = assistant.step(user_msg)
-    assert assistant_response.msgs is not None
-    assert len(assistant_response.msgs) == n
+    assistant_with_sys_msg_response = assistant_with_sys_msg.step(user_msg)
+    assistant_without_sys_msg_response = assistant_without_sys_msg.step(
+        user_msg
+    )
+
+    assert assistant_with_sys_msg_response.msgs is not None
+    assert len(assistant_with_sys_msg_response.msgs) == n
+    assert assistant_without_sys_msg_response.msgs is not None
+    assert len(assistant_without_sys_msg_response.msgs) == n
 
 
 @pytest.mark.model_backend
@@ -396,21 +428,41 @@ def test_set_multiple_output_language():
         meta_dict=None,
         content="You are a help assistant.",
     )
-    agent = ChatAgent(system_message=system_message)
+    agent_with_sys_msg = ChatAgent(system_message=system_message)
+    agent_without_sys_msg = ChatAgent()
 
     # Verify that the length of the system message is kept constant even when
     # multiple set_output_language operations are called
-    agent.set_output_language("Chinese")
-    agent.set_output_language("English")
-    agent.set_output_language("French")
-    updated_system_message = BaseMessage(
+    agent_with_sys_msg.set_output_language("Chinese")
+    agent_with_sys_msg.set_output_language("English")
+    agent_with_sys_msg.set_output_language("French")
+    agent_without_sys_msg.set_output_language("Chinese")
+    agent_without_sys_msg.set_output_language("English")
+    agent_without_sys_msg.set_output_language("French")
+
+    updated_system_message_with_content = BaseMessage(
         role_name="assistant",
         role_type=RoleType.ASSISTANT,
         meta_dict=None,
         content="You are a help assistant."
         "\nRegardless of the input language, you must output text in French.",
     )
-    assert agent.system_message.content == updated_system_message.content
+    updated_system_message_without_content = BaseMessage(
+        role_name="assistant",
+        role_type=RoleType.ASSISTANT,
+        meta_dict=None,
+        content="\nRegardless of the input language, you must output text "
+        "in French.",
+    )
+
+    assert (
+        agent_with_sys_msg.system_message.content
+        == updated_system_message_with_content.content
+    )
+    assert (
+        agent_without_sys_msg.system_message.content
+        == updated_system_message_without_content.content
+    )
 
 
 @pytest.mark.model_backend