LLMs have systematic behavioral blindspots in therapeutic interaction—they over-rely on questioning and under-use teaching—but these gaps can be substantially reduced by exposing therapeutic moves as accessible tools, without retraining.
This paper creates a framework for measuring how LLMs conduct psychotherapy by defining ten therapeutic moves (like inquiry, psychoeducation, validation). Testing frontier models against real therapist transcripts reveals LLMs ask questions 3x more than humans, skip teaching patients, and rarely initiate strategies—but giving models access to these moves as tools cuts this gap in half.