Maze2D hard native256 all-step CoT; key step = LAST decisive branch before goal (lastbranch_v3); aligned 1:1 to plain by __bagel_order_key local source dir: maze2d_hard_native256_stopreq_stepmsg_fixedstart_cot_lastbranch_ordered_20260606_lastbranch_v3 format: trajectories//{train,test}/*.jsonl.gz (ordered by __bagel_order_key); base64 images inline. plain & cot variants are aligned 1:1 by… See the full description on the dataset page: https://huggingface.co/datasets/novastar114/maze2d_hard_native256_cot_lastbranch.