When was Claude Opus 4 released?

Claude Opus 4 was released by Anthropic on Thursday, May 22 2025.

Who made Claude Opus 4?

Claude Opus 4 was built by Anthropic. AI safety company building the Claude family of models. Founded in 2021 by former OpenAI researchers.

What benchmark scores did Claude Opus 4 get?

Claude Opus 4 reports 3 tracked benchmark scores — BullshitBench v2: 34%; SWE-Bench Verified: 72.5%; GPQA Diamond: 79.6%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.

Is Claude Opus 4 open source?

No. Claude Opus 4 is a closed model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

What came before and after Claude Opus 4?

Anthropic's previous tracked release was Claude Sonnet 4 on May 22 2025. It was followed by Claude Opus 4.1 on Aug 5 2025.

Claude Opus 4

Released May 22 2025

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.

Benchmarks

Coding

SWE-Bench Verified

72.5%

#35 of 59

Reasoning & science

GPQA Diamond

79.6%

#38 of 61

Robustness

BullshitBench v2

34%

#57 of 97

Compare Claude Opus 4 with

Claude Opus 4

Suggested comparisons

Claude Opus 4vsClaude Haiku 5.5 Claude Opus 4vsGPT-6.1 Sol Claude Opus 4vsGemini 4 Argon Claude Opus 4vsMuse Spark Open Claude Opus 4vsGrok 4.7 Claude Opus 4vsDeepSeek-V4.1-Flash-1017 Claude Opus 4vsMistral Large 4 Claude Opus 4vsKimi K3 Claude Opus 4vsGLM-5.3-Flash Claude Opus 4vsQwen3.8-Max-0902 Claude Opus 4vsNemotron 3.5 Super VL

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.

Frequently asked questions

: Claude Opus 4 was released by Anthropic on Thursday, May 22 2025.
: Claude Opus 4 was built by Anthropic. AI safety company building the Claude family of models. Founded in 2021 by former OpenAI researchers.
: Claude Opus 4 reports 3 tracked benchmark scores — BullshitBench v2: 34%; SWE-Bench Verified: 72.5%; GPQA Diamond: 79.6%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.
: No. Claude Opus 4 is a closed model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.
: Anthropic's previous tracked release was Claude Sonnet 4 on May 22 2025. It was followed by Claude Opus 4.1 on Aug 5 2025.