Video-STAR: Reinforcing Open-Vocabulary Action Recognition with Tools - Yuan, Zhenlong; Qu, Xiangyan; Qian, Chengxuan; Chen, Rui; Tang, Jing; Sun, Lei; Chu, Xiangxiang; Zhang, Dapeng; Wang, Yiwei; Cai, Yujun; Li, Shuo (International Conference on Learning Representations, 2026)