SciMaster: Towards General-Purpose Scientific AI Agents, Part I. X-Master as Foundation: Can We Lead on Humanity's Last Exam? - Jingyi Chai; Shuo Tang; Rui Ye 001; Yuwen Du; Xinyu Zhu; Mengcheng Zhou; Yanfeng Wang 001; Weinan E; Yuzhi Zhang; Linfeng Zhang 002; Siheng Chen (CoRR, 2025)