create_extraction_chain_pydantic() — langchain Function Reference

Source Code

libs/langchain/langchain_classic/chains/openai_tools/extraction.py lines 53–79

def create_extraction_chain_pydantic(
    pydantic_schemas: list[type[BaseModel]] | type[BaseModel],
    llm: BaseLanguageModel,
    system_message: str = _EXTRACTION_TEMPLATE,
) -> Runnable:
    """Creates a chain that extracts information from a passage.

    Args:
        pydantic_schemas: The schema of the entities to extract.
        llm: The language model to use.
        system_message: The system message to use for extraction.

    Returns:
        A runnable that extracts information from a passage.
    """
    if not isinstance(pydantic_schemas, list):
        pydantic_schemas = [pydantic_schemas]
    prompt = ChatPromptTemplate.from_messages(
        [
            ("system", system_message),
            ("user", "{input}"),
        ],
    )
    functions = [convert_pydantic_to_openai_function(p) for p in pydantic_schemas]
    tools = [{"type": "function", "function": d} for d in functions]
    model = llm.bind(tools=tools)
    return prompt | model | PydanticToolsParser(tools=pydantic_schemas)