Opus 4.5, developed by Anthropic, is a language model specializing in code reviews, distinguished by its ability to audit and refine code architecture systematically. Unlike other models that focus on identifying specific logic errors or style issues, Opus 4.5 conducts in-depth, structured reviews, akin to technical documentation, and addresses broader system-level concerns rather than isolated issues. Integrated into CodeRabbit's benchmarking system, Opus 4.5 is evaluated for precision, importance of comments, and signal-to-noise ratio, showing a balance between high signal density and moderate precision. Its comments are characterized by a consistent structure across multiple programming languages, using a clear rhythm of context, cause, and correction, which enhances readability and trust among developers. The model is noted for its calm and professional tone, which avoids excessive confidence, making its feedback feel reliable and authoritative. While it may occasionally show a subtle confidence inversion when incorrect, overall, Opus 4.5 excels in providing systemic insights and architectural understanding, making it a valuable tool for complex code reviews that require cross-language consistency and broad reasoning.