AI21 Labs Releases LIFT-Bench to Curb Reward Hacking in RL Training

AI21 Labs released LIFT-Bench on October 25, 2026, an instruction-following benchmark in which every constraint is scoped to one section of a document and the task content itself is scored, alongside LIFT-Train, a 34,258-task training counterpart, and the open pipeline that generated both. A companion paper, "LIFT: Scoped Constraints for Evaluating and Training Instruction Following" by Eran Goldstein, Yuval Belfer, Yonatan Belinkov, and Daniel Gissin, was submitted to arXiv on October 20...