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Claude Opus 4.8 released May 28, 2026; SWE-bench Pro score reported to rise from…

2026-05-28 · 17:21 UTC ·@bcherny ·0 min read

Brief

Claude Opus 4.8, released May 28, 2026, is presented as Anthropic's strongest coding model yet: SWE-bench Pro rises from 64.3 to 69.2 versus Opus 4.7. The update reportedly adds sharper judgment, explicit uncertainty signalling, self-bug-catching and longer autonomous work capacity. It’s available today at the same price as Opus 4.7.

Why it matters

Claude Opus 4.8 released May 28, 2026; SWE-bench Pro score reported to rise from 64.3 to 69.2 versus Opus 4.7

Key details

  • Announced as "our strongest coding model yet": claims include sharper judgment, explicit uncertainty signaling (it tells you when it's unsure), self-bug-catching instead of premature victory, and longer independent work capacity
  • Available today at the same price as Opus 4.7 (announcement posted by @bcherny and by Claude/@claudeai)
Source evidence

Claude Opus 4.8 is out today. It's our strongest coding model yet: up on SWE-bench Pro (from 64.3 to 69.2) and noticeably more honest about its own work. It tells you when it's unsure and catches its own bugs instead of declaring victory early. Same price as 4.7.

Claude (@claudeai)

Introducing Claude Opus 4.8: it builds on Opus 4.7 with sharper judgment, more honesty about its own progress, and the ability to work independently for longer than its predecessors.

Available today at the same price.

— https://nitter.net/claudeai/status/2060042702150930686#m