RFC: ChatModel.as_str

libs/core/langchain_core/language_models/chat_models.py

@@ -37,6 +37,7 @@ from langchain_core.messages import (
     convert_to_messages,
     message_chunk_to_message,
 )
+from langchain_core.output_parsers import StrOutputParser
 from langchain_core.outputs import (
     ChatGeneration,
     ChatGenerationChunk,
@@ -49,7 +50,7 @@ from langchain_core.pydantic_v1 import Field, root_validator
 from langchain_core.runnables.config import ensure_config, run_in_executor
 
 if TYPE_CHECKING:
-    from langchain_core.runnables import RunnableConfig
+    from langchain_core.runnables import Runnable, RunnableConfig
 
 
 def _get_verbosity() -> bool:
@@ -311,6 +312,9 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
                     LLMResult(generations=[[generation]]),
                 )
 
+    def as_str(self) -> Runnable[LanguageModelInput, str]:
+        return self | StrOutputParser()
+
     # --- Custom methods ---
 
     def _combine_llm_outputs(self, llm_outputs: List[Optional[dict]]) -> dict: