When to choose Sonnet over Opus, what it costs, and how to tune it (claude.dev)

Anthropic has announced Claude Sonnet 5.5, the second model in its Claude 5.5 family following Opus 5.5. This new model presents significant improvements, being 30% faster and more efficient than its predecessor, Sonnet 5, while maintaining the same per-token pricing. Notably, Sonnet 5.5 typically requires fewer tokens to complete tasks, resulting in potential cost savings of up to 30% for users. This model is tailored for everyday coding tasks such as bug fixes and feature iterations, as well as producing polished documents and spreadsheets. Its design prioritizes speed and quality, making it ideal for well-scoped tasks with clear specifications. This development is significant for the AI/ML community as it enables more efficient resource utilization in AI applications, particularly in software development environments. Sonnet 5.5 operates with a context window of 1 million tokens and supports high-resolution output, while also integrating adaptive thinking capabilities that enhance its responsiveness. Users can expect a smoother transition from previous models due to its design, which allows for effective switching without requiring major prompt changes. As Claude Haiku 5.5 is set to launch, aimed at high-volume, low-latency workflows, the evolution of these models underscores a growing trend towards optimizing AI for specific practical applications.