Claude 4.1 Opus (Reasoning)

Claude 4.1 Opus (Reasoning) is an advanced flagship language model developed by Anthropic, released as an iterative upgrade to the Claude 4 family. It is designed for high-complexity cognitive tasks, particularly in the domains of software engineering, agentic workflows, and deep research. As a hybrid reasoning model, it supports an "extended thinking" mode that allows the model to utilize a dedicated reasoning budget to process complex problems step-by-step before delivering a final response.

The model features a 200,000-token context window and is capable of generating up to 32,000 output tokens, with the reasoning variant specifically supporting up to 64,000 tokens of internal chain-of-thought processing. This architecture is optimized for long-horizon tasks, such as multi-file code refactoring and autonomous data synthesis, where maintaining state and detail tracking over extended sequences is critical.

In technical evaluations, Claude 4.1 Opus achieved a score of 74.5% on SWE-bench Verified, demonstrating a measurable improvement over its predecessor in resolving real-world software issues. It is characterized by high precision in debugging and a reduced tendency to introduce unnecessary changes or regressions in large codebases. The model is multimodal, supporting both text and image inputs for analysis within enterprise-scale technical workflows.