Make ChatAgent an ABC

python/packages/autogen-agentchat/src/autogen_agentchat/base/_chat_agent.py

@@ -1,5 +1,6 @@
+from abc import ABC, abstractmethod
 from dataclasses import dataclass
-from typing import Any, AsyncGenerator, Mapping, Protocol, Sequence, runtime_checkable
+from typing import Any, AsyncGenerator, Mapping, Sequence
 
 from autogen_core import CancellationToken
 
@@ -19,52 +20,60 @@ class Response:
     or :class:`ChatMessage`."""
 
 
-@runtime_checkable
-class ChatAgent(TaskRunner, Protocol):
+class ChatAgent(ABC, TaskRunner):
     """Protocol for a chat agent."""
 
     @property
+    @abstractmethod
     def name(self) -> str:
         """The name of the agent. This is used by team to uniquely identify
         the agent. It should be unique within the team."""
         ...
 
     @property
+    @abstractmethod
     def description(self) -> str:
         """The description of the agent. This is used by team to
         make decisions about which agents to use. The description should
         describe the agent's capabilities and how to interact with it."""
         ...
 
     @property
+    @abstractmethod
     def produced_message_types(self) -> Sequence[type[ChatMessage]]:
         """The types of messages that the agent produces in the
         :attr:`Response.chat_message` field. They must be :class:`ChatMessage` types."""
         ...
 
+    @abstractmethod
     async def on_messages(self, messages: Sequence[ChatMessage], cancellation_token: CancellationToken) -> Response:
         """Handles incoming messages and returns a response."""
         ...
 
+    @abstractmethod
     def on_messages_stream(
         self, messages: Sequence[ChatMessage], cancellation_token: CancellationToken
     ) -> AsyncGenerator[AgentEvent | ChatMessage | Response, None]:
         """Handles incoming messages and returns a stream of inner messages and
         and the final item is the response."""
         ...
 
+    @abstractmethod
     async def on_reset(self, cancellation_token: CancellationToken) -> None:
         """Resets the agent to its initialization state."""
         ...
 
+    @abstractmethod
     async def save_state(self) -> Mapping[str, Any]:
         """Save agent state for later restoration"""
         ...
 
+    @abstractmethod
     async def load_state(self, state: Mapping[str, Any]) -> None:
         """Restore agent from saved state"""
         ...
 
+    @abstractmethod
     async def close(self) -> None:
         """Called when the runtime is stopped or any stop method is called"""
         ...