Ego-R1: Chain-of-Tool-Thought for Ultra-Long Egocentric Video Reasoning. - Shulin Tian; Ruiqi Wang; Hongming Guo; Penghao Wu; Yuhao Dong; Xiuying Wang 012; Jingkang Yang; Hao Zhang 097; Hongyuan Zhu; Ziwei Liu 002 (CoRR, 2025)