Returns the assistant's reasoning trace (if any). Only LLMMessage objects carry a reasoning
field; all other Message subclasses return NA_character_. Messages whose reasoning is unset
(NULL) also return NA_character_.
Returns the assistant's reasoning trace (if any). Only LLMMessage objects carry a reasoning
field; all other Message subclasses return NA_character_. Messages whose reasoning is unset
(NULL) also return NA_character_.