ToolGym: an Open-world Tool-using Environment for Scalable Agent Testing and Data Curation. - Ziqiao Xi; Shuang Liang; Qi Liu; Jiaqing Zhang; Letian Peng; Fang Nan; Meshal Nayim; Tianhui Zhang; Rishika Mundada; Lianhui Qin; Biwei Huang; Kun Zhou (CoRR, 2026)