Anthropic released Claude Sonnet 5.5, a new AI model positioned as a faster and more cost-effective option for developers and enterprises. The model is priced at $2 per million input tokens and $10 per million output tokens, exactly half the cost of the recently launched Opus 5.5. Anthropic states Sonnet 5.5 outperforms its predecessor in programming, clearly scoped tasks, and document creation including slides and spreadsheets. While not designed to push frontier capabilities, Sonnet 5.5 features significantly improved cybersecurity defenses compared to previous versions. It is the first Sonnet model to launch with backup protection and cyber defense measures comparable to higher-tier models. The release comes less than a week after Opus 5.5, with Anthropic confirming that Haiku 5.5, the cheapest model in the series, will arrive soon.