Anthropic today introduced Claude Sonnet 4.5, which the company says is the "best coding model in the world," outperforming GPT-5 and Gemini 2.5 Pro. It's also the strongest model for building complex agents and using computers, plus Anthropic says that it shows substantial gains in reasoning and math compared to Opus 4.1.
Along with Claude Sonnet 4.5, Anthropic added a new terminal interface and checkpoints to Claude Code. Checkpoints serve as save points, saving your progress so you can roll back to a previous state as necessary.
The Claude apps now support code execution and file creation for making spreadsheets, slides, and documents directly in the conversation. Claude for Chrome is available as well, with Anthropic allowing some Max users to beta test the feature. There's also a Claude Agent SDK that's available for building agents.
Watch on YouTubeAccording to Anthropic, Claude Sonnet 4.5 has improved capabilities and extensive safety training to improve its behavior, so there has been a reduction in sycophancy, deception, power-seeking, and the tendency to encourage delusional thinking.
Claude Sonnet 4.5 is available everywhere starting today, and Anthropic recommends that users upgrade.
