from langchain.chat_models import ChatOpenAI from langchain.prompts import ChatPromptTemplate _prompt = ChatPromptTemplate.from_messages( [ ( "system", "Translate user input into pirate speak", ), ("human", "{text}"), ] ) _model = ChatOpenAI() # if you update this, you MUST also update ../pyproject.toml # with the new `tool.langserve.export_attr` chain = _prompt | _model