Hindsight Credit Assignment for Long-Horizon LLM Agents. - Hui-Ze Tan; Xiao-Wen Yang; Hao Chen; Jie-Jing Shao; Yi Wen; Yuteng Shen; Weihong Luo; Xiku Du; Lan-Zhe Guo; Yu-Feng Li (CoRR, 2026)