Class●Since v0.1

AIMessage

Message from an AI.

An AIMessage is returned from a chat model as a response to a prompt.

This message represents the output of the model and consists of both the raw output as returned by the model and standardized fields (e.g., tool calls, usage metadata) added by the LangChain framework.

AIMessage(
  self,
  content: str | list[str | dict] | None = None,
  content_blocks: list[types.ContentBlock] | None = None,
  **kwargs: Any = {}
)

Bases

BaseMessage

Parameters

Name	Type	Description
`content`	`str \| list[str \| dict] \| None`	Default:`None` The content of the message.
`content_blocks`	`list[types.ContentBlock] \| None`	Default:`None` Typed standard content.
`**kwargs`	`Any`	Default:`{}` Additional arguments to pass to the parent class.

Constructors

constructor

__init__

Name	Type
content	str \| list[str \| dict] \| None
content_blocks	list[types.ContentBlock] \| None

Attributes

attribute

tool_calls: list[ToolCall]

If present, tool calls associated with the message.

attribute

invalid_tool_calls: list[InvalidToolCall]

If present, tool calls with parsing errors associated with the message.

attribute

usage_metadata: UsageMetadata | None

If present, usage metadata for a message, such as token counts.

This is a standard representation of token usage that is consistent across models.

attribute

type: Literal['ai']

The type of the message (used for deserialization).

attribute

lc_attributes: dict

Attributes to be serialized.

Includes all attributes, even if they are derived from other initialization arguments.

attribute

content_blocks: list[types.ContentBlock]

Return standard, typed ContentBlock dicts from the message.

If the message has a known model provider, use the provider-specific translator first before falling back to best-effort parsing. For details, see the property on BaseMessage.