GPT-5.5 was used to flag fatal errors in FrontierMath problems

FrontierMath is supposed to be one of the hard benchmarks for frontier models, and now Epoch is saying an AI-assisted review found fatal errors in about a third of Tiers 1-4.

Noam Brown says the initial flags came from GPT-5.5.

Obviously we’ll have to wait for the corrected scores, but this is a pretty interesting moment: the model is already strong enough to sanity-check the benchmark.