Claude Opus 4
Released
Claude Opus 4 is an AI model released by Anthropic on Thursday, May 22 2025, the same day as Claude Sonnet 4. Benchmark results (shown below) cover BullshitBench v2, SWE-Bench Verified, and GPQA Diamond.
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Benchmarks
Coding
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Robustness
About
Claude Opus 4 arrived May 22, 2025 together with Claude Sonnet 4, reviving the Opus tier after more than a year and marking Anthropic's pivot to long-horizon agentic work. It was pitched at sustained, multi-hour coding sessions — refactoring across large codebases, running in agent harnesses, and using tools in extended loops — rather than single-shot chat answers.
It posted 79.6% on GPQA Diamond and 72.5% on SWE-Bench Verified, roughly ten points above Claude 3.7 Sonnet on software engineering. Claude Opus 4.1 followed on August 5, 2025 as an incremental refinement, and the Opus line has since been Anthropic's flagship tier through Opus 4.5 and beyond.
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Frequently asked questions
Claude Opus 4 was released by Anthropic on Thursday, May 22 2025.