Anthropic has introduced the discharge of Claude Sonnet 4.5, which it claims is the “finest coding mannequin on the planet” and the “strongest mannequin for constructing advanced brokers.”
It achieves a 77.2% on the SWE-bench for software program engineering, in comparison with 74.5% for Claude Opus 4.1 and 72.7% for Claude Sonnet 4. For exterior comparability, GPT-5 Codex scored at 74.5%, GPT-5 scored 72.8%, and Gemini 2.5 Professional scored 67.2%.
Moreover, it leads within the OSWorld benchmark, which assessments AI fashions on real-world pc duties. It scored 61.4% on that benchmark, beating out Claude Sonnet 4, which scored 42.2%.
“Sonnet 4.5 can produce near-instant responses or prolonged, step-by-step pondering that’s made seen to the person,” Anthropic says.
In response to Anthropic, Claude Sonnet 4.5 additionally exhibits higher domain-specific information and reasoning within the fields of finance, legislation, and drugs.
This mannequin performs higher on security and alignment evaluations, the corporate claims. It exhibits a discount in behaviors resembling sycophancy, deception, power-seeking, and the tendency to encourage delusional pondering, in addition to exhibiting progress on having the ability to defend towards immediate injection assaults.
The pricing for Claude Sonnet 4.5 is identical as Claude Sonnet 4’s pricing: $3 per million enter tokens and $15 per million output tokens.
Alongside the launch of Claude Sonnet 4.5, Anthropic additionally introduced updates throughout a number of of its merchandise. Claude Code now has checkpoints that enable builders to save lots of their progress and roll again to earlier variations. The Claude API received a brand new context modifying function and reminiscence software that allows brokers to run longer and deal with extra advanced duties. Moreover, all Claude apps now have entry to code execution and file creation.
The corporate can also be releasing the Claude Agent SDK, which builders can use to construct their very own brokers utilizing the identical infrastructure Anthropic makes use of to energy Claude Code.
“We constructed Claude Code as a result of the software we needed didn’t exist but. The Agent SDK provides you a similar basis to construct one thing simply as succesful for no matter drawback you’re fixing,” Anthropic wrote in a weblog submit.