Claude Sonnet 4 is an AI model released by Anthropic on May 22 2025, 87 days after Claude 3.7 Sonnet. It is the 11th tracked release from Anthropic out of 19 total.
On published benchmarks, it scores 75.4% on GPQA Diamond (graduate-level science reasoning), 72.7% on SWE-Bench Verified (real-world software engineering).
About Anthropic: AI safety company building the Claude family of models. Founded in 2021 by former OpenAI researchers.