TL;DR: I gave Claude Fable 5 and GPT-5.6 Sol the same unpublished NP-hard optimization problem, with and without their native /goal mode. Fable 5 is an absolute beast; /goal is not a game changer. Context: This is an operations research problem originally submitted to students at a hackathon. I spent a week years ago writing C++ to solve it, so I have a useful human baseline. Fable 5 was an absolute beast on this benchmark. It produced the best solution overall, and its consistency is unlike anything I have seen from a model on this problem. This is pure raw intelligence. Incredible. The other result is that /goal is not a generic “try harder” switch. It changes the control loop and the search path. Sometimes that finds a better basin. Sometimes it gives a bad idea more time to mature. All code, prompts, result tables, exclusions, and trajectory notes are in CLIArena . This is a follow-up to my first article about this benchmark .…