--- title: Claude Opus 5.5 uses 95% fewer em dashes, but its... description: New analysis from AI benchmarking tool Arena shows Claude Opus 5.5 has shifted its writing style compared to Opus 5, dropping em dash usage per 1,000 words... canonical: https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Claude Opus 5.5 uses 95% fewer em dashes, but its answers are getting longer | daily.dev og:description: New analysis from AI benchmarking tool Arena shows Claude Opus 5.5 has shifted its writing style compared to Opus 5, dropping em dash usage per 1,000 words... og:url: https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4 og:image: https://api.daily.dev/og/posts/8bgCmMmU4.png og:image:alt: Claude Opus 5.5 uses 95% fewer em dashes, but its answers are getting longer og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Claude Opus 5.5 uses 95% fewer em dashes, but its answers are getting longer **[BleepingComputer](https://daily.dev/sources/bleepingcomputer)** · 2 min read · 0 upvotes · 0 comments ## Summary New analysis from AI benchmarking tool Arena shows Claude Opus 5.5 has shifted its writing style compared to Opus 5, dropping em dash usage per 1,000 words from 15.2 to 0.8 (a 95% reduction) and semicolon usage from 6.10 to 1.64. Sentences also got shorter, averaging 10.03 words versus 12.14 previously. However, responses grew more verbose overall, with average answer length increasing from 453 to 481 words, making it the longest-writing Opus model measured so far. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How much did em dash usage change between Claude Opus 5 and Opus 5.5? Em dash usage dropped by roughly 95%, from 15.2 per 1,000 words in Opus 5 to just 0.8 per 1,000 words in Opus 5.5. Semicolon usage also fell sharply, from 6.10 to 1.64 per 1,000 words, based on analysis of high-reasoning Text Arena responses collected in August and September 2026. _Track how model updates like this affect writing style and coding output on daily.dev._ ### Are Claude Opus 5.5 responses longer or shorter than Opus 5? Opus 5.5 writes shorter sentences but longer overall answers than Opus 5. Average sentence length dropped from 12.14 to 10.03 words, while average answer length increased from 453 to 481 words, making Opus 5.5 the most verbose Opus model measured in this comparison despite its simpler phrasing. _Developers weighing model verbosity trade-offs can follow these shifts on daily.dev._ --- Tags: [#claude](https://daily.dev/tags/claude), [#anthropic](https://daily.dev/tags/anthropic) [View this post on daily.dev](https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Claude Opus 5.5 uses 95% fewer em dashes, but its answers are getting longer","url":"https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4"},"datePublished":"2026-09-26T16:29:12.265Z","dateModified":"2026-09-26T18:36:29.687Z","description":"New analysis from AI benchmarking tool Arena shows Claude Opus 5.5 has shifted its writing style compared to Opus 5, dropping em dash usage per 1,000 words...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3343c0898657a5738acd40fd1a4012cf?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3343c0898657a5738acd40fd1a4012cf?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"BleepingComputer","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"BleepingComputer","logo":"https://media.daily.dev/image/upload/s--as8nJ3qy--/f_auto,q_auto/v1774959951/logos/bleepingcomputer?_a=BAMAMiWQ0","url":"https://daily.dev/sources/bleepingcomputer"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"claude,anthropic","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"BleepingComputer","item":"https://daily.dev/sources/bleepingcomputer"},{"@type":"ListItem","position":3,"name":"Claude Opus 5.5 uses 95% fewer em dashes, but its answers are getting longer"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/claude-opus-5-5-uses-95-fewer-em-dashes-but-its-answers-are-getting-longer-8bgcmmmu4#faq","mainEntity":[{"@type":"Question","name":"How much did em dash usage change between Claude Opus 5 and Opus 5.5?","acceptedAnswer":{"@type":"Answer","text":"Em dash usage dropped by roughly 95%, from 15.2 per 1,000 words in Opus 5 to just 0.8 per 1,000 words in Opus 5.5. 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