Claude Opus 5和Opus 4.5差多少？LMArena用数据告诉你：回复长度是4.5的3倍，词汇反而更简单，破折号也更多。
LMArena分析了数万条Claude Opus和Fable从4.5到5版本的真实高推理输出。Opus 5平均每响应510个词，是Opus 4.5平均158个词的3倍多。句子长度上升58%，从句频率上升46%，但长实词占比从46.9%降至40.1%，抽象名词每千词从6.02个降至3.79个。Opus 5的破折号使用量是4.5的2.3倍，'honestly'等诚实类措辞增加50%。Fable 5平均316个词，比Opus 5短38%，但包含赞扬或'yes, exactly'式开头的概率接近2倍。
We analyzed tens of thousands of real-world, high-reasoning Claude Opus and Fable outputs from versi...
We analyzed tens of thousands of real-world, high-reasoning Claude Opus and Fable outputs from versions 4.5 to 5 in the Text Arena and found that @claudeai 's writing has changed in more ways than one: Across language complexity, patterns and markers, we now see: Claude’s answers have become much longer: - Opus 5 averages 510 words per response - This makes Opus 5 responses 3x longer than Opus 4.5’s average of 158 Responses have also become more structurally elaborate from Opus 4.5 to Opus 5: - 58% rise in average sentence length - 46% rise in clause frequency rises However, the vocabulary itself is not becoming more difficult, making Opus 5 longer and more structurally complex, but lexically simpler between 4.5 and 5: - 6.8% pt drop in long content words (46.9% to 40.1%) - 53% drop in abstract nouns (6.02 → 3.79 per 1k words) Writing habits people notice are much more common in Opus 5: - 2.3x as many em dashes - ~2x as many phrases like “load-bearing” - 50% more honesty wording like “honestly” and “frankly” Fable 5 is 38% more concise than Opus 5, averaging 316 words vs. 510. At the same time, it is nearly 2x as likely to include praise/validation or open with phrases like “yes, exactly” 💬 7 🔄 1 ❤️ 50 👀 3359 📊 12 ⚡