Metadata for messages the agent harness adds to a conversation.
Return a copy of message marked as added by the agent harness.
Use it for a human message the user didn't type, such as a background task
update or a conversation summary. It sets additional_kwargs["lc_source"]
and, when data is given, additional_kwargs["lc_data"]. Any earlier
lc_source and lc_data are removed first. LangChain's chat model
integrations don't send these keys to the model.
It doesn't change the content. Write the content the model reads yourself.
Anyone who can send input to a thread can set these keys. Don't use them to decide whether to trust a message.
merge_message_runs and chunk addition join a notification with adjacent
human messages; the merged message keeps the metadata and concatenates
lc_source.
Return the notification metadata of message.
Base abstract message class.
Messages are the inputs and outputs of a chat model.
Examples include HumanMessage,
AIMessage, and
SystemMessage.
Message from the user.
A HumanMessage is a message that is passed in from a user to the model.
Which feature added a message, and that feature's fields.
