chat_generation.py — langchain Source File

Source Code

"""Chat generation output classes."""

from __future__ import annotations

from typing import TYPE_CHECKING, Literal

from pydantic import model_validator

from langchain_core.messages import BaseMessage, BaseMessageChunk
from langchain_core.outputs.generation import Generation
from langchain_core.utils._merge import merge_dicts

if TYPE_CHECKING:
    from typing_extensions import Self


class ChatGeneration(Generation):
    """A single chat generation output.

    A subclass of `Generation` that represents the response from a chat model that
    generates chat messages.

    The `message` attribute is a structured representation of the chat message. Most of
    the time, the message will be of type `AIMessage`.

    Users working with chat models will usually access information via either
    `AIMessage` (returned from runnable interfaces) or `LLMResult` (available via
    callbacks).
    """

    text: str = ""
    """The text contents of the output message.

    !!! warning "SHOULD NOT BE SET DIRECTLY!"

    """
    message: BaseMessage
    """The message output by the chat model."""

    # Override type to be ChatGeneration, ignore mypy error as this is intentional
    type: Literal["ChatGeneration"] = "ChatGeneration"  # type: ignore[assignment]
    """Type is used exclusively for serialization purposes."""

    @model_validator(mode="after")
    def set_text(self) -> Self:
        """Set the text attribute to be the contents of the message.

        Args:
            values: The values of the object.

        Returns:
            The values of the object with the text attribute set.

        Raises:
            ValueError: If the message is not a string or a list.
        """
        text = ""
        if isinstance(self.message.content, str):
            text = self.message.content
        # Extracts first text block from content blocks.
// ... (87 more lines)