Retrieves and parses the assistant's reply as JSON from an LLMMessage
object at a specified index.
If the reply is not marked as JSON, attempts to extract JSON content from text.
get_reply_data(.llm, .index = NULL)
Parsed data content of the assistant's reply, or NULL
if parsing fails.
An LLMMessage
object containing the message history.
A positive integer for the assistant reply index to retrieve, defaulting to the last reply.