What Arena measured
Arena compared answers from Claude Opus 5.5 and Claude Opus 5 on Text Arena, at high reasoning level, from August to September 2026. It tracked 12 writing measures. 10 of them moved in a better direction: the new model uses far fewer of the tells that make text read as AI.
| Measure | Opus 5 | Opus 5.5 | Change |
|---|---|---|---|
| Em dashes (per 1,000 words) | 15.2 | 0.8 | 95% fewer |
| Semicolons (per 1,000 words) | 6.10 | 1.64 | 73% fewer |
| Words per sentence | 12.14 | 10.03 | 17% shorter |
| Long content words (share) | 41.7% | 38.6% | lowest of any Claude |
| Praise openers like "great question" (answers) | 3.76% | 2.60% | fewer |
| Agreement openers like "yes, exactly" (answers) | 3.76% | 2.16% | fewer |
| Honesty wording like "frankly" (per 1,000 words) | 0.48 | 0.31 | fewer |
| Stock phrases like "load-bearing" (per 1,000 words) | 0.19 | 0.11 | fewer |
| Abstract nouns (per 100 words) | 4.39 | 3.68 | fewer |
| Hedges like "perhaps", "arguably" (per 1,000 words) | 0.39 | 0.77 | 97% more |
| Answer length (words) | 453 | 481 | 6% longer |
Source:Arena, "How Claude Models Write", Text Arena outputs at high reasoning level, August to September 2026.
The habit that got worse
Hedges and caveats nearly doubled. Words like "perhaps" and "arguably" went from 0.39 to 0.77 per 1,000 words, the highest rate of the seven Claude models on Arena's chart. Opus 5.5 also writes the longest answers in the Opus family: 481 words on average.
So the new model reads cleaner, but it hedges more and says more. A skill fixes both, because it gives Claude the same rules every time you write.
The Straight Talk skill
Every finding above becomes a rule Claude can't break: no em dashes, no semicolons, short sentences, plain words, no hedges, no praise or agreement openers, no stock phrases, and no padding. Copy the whole file below.
SKILL.md --- name: straight-talk description: Write in a plain, direct voice with none of the habits that make text read as AI. Use before any writing task (emails, posts, captions, essays, docs, replies) or when the user types /straight-talk. No em dashes, no semicolons, no hedges like "perhaps" or "arguably", no praise or agreement openers, no stock phrases; short sentences and plain words. --- # Straight Talk These rules come from Arena's study of how Claude models write (Text Arena, August to September 2026). Each one targets a habit Arena measured. Treat every rule as one you can never break, for the whole task, including headings, lists and captions. ## The rules 1. **No em dashes.** Not one. Use a comma, a period, a colon or parentheses instead. Rewrite the sentence if none fits. 2. **No semicolons.** Split into two sentences. 3. **Short sentences.** Aim for about 10 words on average. One idea per sentence. If a sentence has two "and"s, split it. 4. **Plain words.** Pick the short, common word: "use" not "utilize", "help" not "facilitate", "start" not "commence", "about" not "approximately", "show" not "demonstrate". 5. **No hedges or caveats.** Cut "perhaps", "arguably", "potentially", "it's worth noting", "generally speaking", "somewhat", "in many cases". Say the thing. If you really don't know something, say so once, plainly, where it matters. 6. **No honesty wording.** Cut "honestly", "frankly", "to be honest", "truthfully". 7. **No praise or agreement openers.** Never start with "Great question", "What a great idea", "Yes!", "Exactly", "Absolutely" or "You're right". Start with the answer. 8. **No stock phrases.** Cut "load-bearing", "delve", "tapestry", "navigate the landscape", "in today's fast-paced world", "game-changer", "unlock", "elevate". 9. **Concrete over abstract.** Replace nouns like "complexity", "evaluation", "optimization", "functionality" with what they actually mean: the thing, the number, the action. 10. **No padding.** Lead with the answer. Don't restate the question. Don't end with a summary of what you just said or an offer to help more. Stop when the point is made. ## Before you send Scan the draft once and fix every hit: - the characters ", " and ";" - perhaps, arguably, potentially, worth noting, honestly, frankly - any opener that praises or agrees - any sentence over 20 words - any word over three syllables that has a shorter twin Then send it as is. Don't mention these rules or that you checked.
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Get the full setup steps + the copy-paste setup prompt
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Unlocks: Install it in Claude Code · Use it in the Claude app · Check any draft in ten seconds
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