Claude Sonnet 4.5 is a cutting-edge coding model that excels in building complex agents, improving reasoning, and enhancing math capabilities, marking a significant advancement in AI technology. It features major upgrades, including checkpoints, a refreshed terminal interface, and a native VS Code extension, along with a new context editing feature and memory tool for the Claude API. The model has demonstrated state-of-the-art performance on the SWE-bench Verified evaluation and has shown remarkable improvements in various domains like finance, law, medicine, and engineering. Claude Sonnet 4.5's capabilities are further enhanced by the Claude Agent SDK, enabling developers to build their own agents with the same infrastructure. The model is released under AI Safety Level 3 protections, with measures to mitigate risks such as deception and prompt injection attacks. It is available globally at the same price as its predecessor, offering improved performance for developers and users across multiple platforms.