Claude Opus 4.1, released by Anthropic in August 2025, is a major upgrade to the Claude Opus series, designed to enhance both its reasoning capabilities and its ability to perform complex tasks autonomously. Building upon the previous version, Opus 4.1 significantly improves its performance in various benchmarks, particularly excelling in code comprehension and debugging tasks.

One of the key improvements in Claude Opus 4.1 is its advanced coding capabilities, achieving a 74.5% score on the SWE-bench Verified test, a substantial leap from Opus 4's 72.5%. It also outperforms competitors like Sonnet 3.7 in terms of code refactoring and error detection, particularly in large codebases. Opus 4.1 excels at identifying the root causes of issues without introducing unnecessary changes.

Furthermore, Opus 4.1 is equipped with a maximum output token capacity of 64K, enabling it to handle long-form tasks that require extended focus and consistency over time. This makes it especially suitable for complex, multi-step processes where maintaining coherence and detail is essential. In addition, the model demonstrates impressive performance in general reasoning and data analysis, making it a powerful tool for a wide range of applications.