all_turns() (the default): every earlier turn of the branch. Running out
of the model's context, and being told, is better than a model that
silently misses what was said. last_turns(n): only the last n; the
others are still kept, and each turn's record says which turns it was
shown. without: inputs or outputs left out of every earlier turn (a
long document the model already answered about).
Value
A context rule, for ai_conversation().