Class RunnableBinding

libs/core/langchain_core/runnables/base.py:4820–5013

Wrap a Runnable with additional functionality. A RunnableBinding can be thought of as a "runnable decorator" that preserves the essential features of Runnable; i.e., batching, streaming, and async support, while adding additional functionality. Any class that inherits from Runnable

class RunnableBinding(RunnableBindingBase[Input, Output]):
    """Wrap a Runnable with additional functionality.

    A RunnableBinding can be thought of as a "runnable decorator" that
    preserves the essential features of Runnable; i.e., batching, streaming,
    and async support, while adding additional functionality.

    Any class that inherits from Runnable can be bound to a `RunnableBinding`.
    Runnables expose a standard set of methods for creating `RunnableBindings`
    or sub-classes of `RunnableBindings` (e.g., `RunnableRetry`,
    `RunnableWithFallbacks`) that add additional functionality.

    These methods include:
    - `bind`: Bind kwargs to pass to the underlying runnable when running it.
    - `with_config`: Bind config to pass to the underlying runnable when running it.
    - `with_listeners`:  Bind lifecycle listeners to the underlying runnable.
    - `with_types`: Override the input and output types of the underlying runnable.
    - `with_retry`: Bind a retry policy to the underlying runnable.
    - `with_fallbacks`: Bind a fallback policy to the underlying runnable.

    Example:

    `bind`: Bind kwargs to pass to the underlying runnable when running it.

        .. code-block:: python

            # Create a runnable binding that invokes the ChatModel with the
            # additional kwarg `stop=['-']` when running it.
            from langchain_community.chat_models import ChatOpenAI
            model = ChatOpenAI()
            model.invoke('Say "Parrot-MAGIC"', stop=['-']) # Should return `Parrot`
            # Using it the easy way via `bind` method which returns a new
            # RunnableBinding
            runnable_binding = model.bind(stop=['-'])
            runnable_binding.invoke('Say "Parrot-MAGIC"') # Should return `Parrot`

        Can also be done by instantiating a RunnableBinding directly (not recommended):

        .. code-block:: python

            from langchain_core.runnables import RunnableBinding
            runnable_binding = RunnableBinding(
                bound=model,
                kwargs={'stop': ['-']} # <-- Note the additional kwargs
            )
            runnable_binding.invoke('Say "Parrot-MAGIC"') # Should return `Parrot`
    """

    @classmethod
    def get_lc_namespace(cls) -> List[str]:
        """Get the namespace of the langchain object."""
        return ["langchain", "schema", "runnable"]

    def bind(self, **kwargs: Any) -> Runnable[Input, Output]:
        """Bind additional kwargs to a Runnable, returning a new Runnable.

        Args:
            **kwargs: The kwargs to bind to the Runnable.