X Square Robot open-sources HOST framework; robots can learn new skills from a 29-second video

X Square Robot has released and open-sourced the HOST framework, in which a robot can reproduce a new skill after watching an average 29-second human demonstration video, achieving a 62% success rate with only 1/50 the data and 1/500 the learning time of the Pi-0.5 fine-tuning approach. HOST does not imitate human actions frame by frame; instead, it uses visual outcomes as an intermediate language, aligning video with robot execution by task progress rather than time. It adopts a dual-expert MoT architecture, with learning occurring at the inference stage while weights stay frozen, and it retains old skills better than the fine-tuning approach; under lighting and scene changes, the success rate remains above 50%. The paper and code have been open-sourced.