Leaked GPT-5.5 trace suggests 'caveman mode' thinking secret

A Reddit post by u/JustFinishedBSG claims to have seen GPT-5.5 leak its trace during a normal conversation, describing it as resembling the "caveman mode" fad. The user suggests that better token efficiency could be achieved by taking high-quality thinking traces from an open model, "caveman-izing" them, and fine-tuning on them. The full log of GPT-5.5 going insane is linked in the post.