The truncation strategy to use for the thread. The default is auto. If set to
last_messages, the thread will be truncated to the n most recent messages in
the thread. When set to auto, messages in the middle of the thread will be
dropped to fit the context length of the model, max_prompt_tokens.
Optionallast_The number of most recent messages from the thread when constructing the context for the run.
Controls for how a thread will be truncated prior to the run. Use this to control the intial context window of the run.