Claude Opus 4.5 is an AI model released by Anthropic on Nov 24 2025, 40 days after Claude Haiku 4.5. It is the 16th tracked release from Anthropic out of 19 total.
On published benchmarks, it scores 87% on GPQA Diamond (graduate-level science reasoning), 80.9% 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.