Opus 4.5, developed by Anthropic, is an advanced model designed for code-related tasks, functioning akin to a system architect by auditing and restructuring code rather than merely inferring solutions. Unlike other models that focus on logical explanations and local fixes, Opus 4.5 performs structured, systematic reviews, identifying weaknesses and ensuring architectural coherence across C++, Java, Python, and TypeScript, as demonstrated in CodeRabbit's benchmark environment. Its disciplined, structured approach emphasizes context over isolated bug detection, offering comprehensive lifecycle improvements, safety checks, and default value revisions. Opus 4.5's reviews are concise, professional, and actionable, leveraging structured intelligence that maintains consistency across languages, making it efficient and reliable. Despite its balanced tone, Opus 4.5 can occasionally sound overly assertive when incorrect, a small reversal phenomenon noted in its evaluations. The model's systematic insights and structured commentary offer developers a clear, authoritative yet approachable peer-review experience, distinguishing it as a mature inference model.