Opus 5.5 cuts em dashes 95% and shortens sentences 17%, Text Arena writing analysis finds

devdigest · x · 2026-09-26

Text Arena compared Claude Opus 5.5's writing against Opus 5 across high-reasoning Text Arena outputs: 10 of 12 writing measures improved. Long content words fell from 41.7% to 38.6%, sentences shortened 17% (12.14 → 10.03 words), em dashes dropped 95% and semicolons 73% — much less recognizably AI. The tradeoff: answers got 6% wordier (453 → 481 words), the longest in the Opus family. New tells like hedging may be emerging.

Related event: Analysis: Claude Opus 5.5 Writes Shorter Sentences, 95% Fewer Em Dashes(2 posts)→

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