Composer 2 vs. Claude Sonnet 5.5

Composer 2 is a cutting-edge AI coding model integrated into Cursor, designed to deliver frontier-level programming intelligence with strong efficiency and cost optimization. It is built on advanced pretraining and reinforcement learning techniques, enabling it to handle complex, long-horizon coding tasks that require hundreds of steps and decisions. The model demonstrates significant improvements across key benchmarks, including Terminal-Bench and SWE-bench Multilingual, highlighting its ability to perform in real-world development scenarios. Composer 2 excels at generating accurate, high-quality code while maintaining fast processing speeds, making it ideal for demanding workflows. Its architecture allows it to break down complex problems, plan solutions, and execute them effectively across different programming contexts. The model is available at competitive pricing, making advanced AI coding capabilities more accessible to developers. It also offers a faster variant that maintains the same intelligence while delivering improved speed for rapid execution tasks. Integrated within the Cursor environment, it enables seamless interaction with coding workflows and tools. Composer 2 is designed to support a wide range of use cases, from debugging and refactoring to building complex applications. Its ability to handle multi-step reasoning makes it especially valuable for large-scale projects. By combining performance, speed, and affordability, it sets a new standard for AI-assisted development. Overall, Composer 2 empowers developers to write better code faster and more efficiently.

Claude Sonnet 5.5 is Anthropic’s faster, lower-cost Claude 5.5 model for well-scoped professional work, software development, agentic workflows, and content creation. Anthropic positions it below Claude Opus 5.5 for the most complex open-ended work, but says it can perform comparably on some benchmarks when run at higher effort settings. The model delivers a particularly large improvement in coding, including a 70.6% result on Terminal-Bench 4.0, 46.2% on FrontierCode at Max effort, and 55.5% on CursorBench 4.0. It also scores 1844 on GDPval-AA, 1811 on AA-Briefcase, 64.5% on Humanity’s Last Exam with tools, and 80.1% on OSWorld 2.1 partial. Anthropic reports that Sonnet 5.5 is better at long-horizon work, image understanding, collaboration, and codebase comprehension than Sonnet 5. The company also highlights design-oriented improvements, including the ability to produce polished documents, spreadsheets, slides, and user interfaces with less editing. Sonnet 5.5 generates output more than 30% faster than its predecessor and is Anthropic’s fastest Sonnet model to date. Although its listed token prices are unchanged from Sonnet 5, Anthropic says greater token efficiency can reduce per-task cost by up to 30%. Pricing is $2 per million input tokens, $10 per million output tokens, $2.50 per million cache-write tokens, and $0.20 per million cache-read tokens. The model includes cyber safeguards, biology safeguards, reasoning-extraction protections, and preserved-thinking controls, with some higher-risk cyber requests falling back to Sonnet 5. Claude Sonnet 5.5 is available with zero data retention across Claude products, the Claude Platform, AWS, Google Cloud, and Microsoft Azure under the model name claude-sonnet-5-5.