These models won't play chess at all without a prompt. A substantial portion of a finding like this is a finding about the prompt. It still counts as a finding

These models won't play chess at all without a prompt. A substantial portion of a finding like this is a finding about the prompt. It still counts as a finding about the model and perhaps about inference code (which may inject extra reasoning tokens or reject end-of-reasoning tokens to produce longer reasoning sections), but really it's about the interaction between the three things. If someone were to deploy a chess playing application backed by these models, they would put a fair bit of work into their prompt. Maybe these results would never apply, or maybe these results would be the first thing they fix, almost certainly trivially.