Ethan Mollick: Opus 4.7-5 lost the 'Claude feel', Opus 5.5 brings it back

emollick · x · 2026-09-27

Ethan Mollick argues model personality matters in ways benchmarks can't capture: the Opus line went through a rough patch from 4.7 to 5 where it no longer felt "Claude-y" — more like a watered-down Fable, possibly due to teacher-model distillation — while Opus 5.5 feels like working with ol' Claude again.

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