The model comes hot on the heels of Opus 4.1, the launch of file creation and Claude for Chrome, which all seem to be included in this release.
Claude Code gets what users want
There are also updates to Claude Code, where Anthropic is checking off the most requested features, like checkpoints that will save your progress and let you fall back instantly if you are experimenting.
There is also now a native VS code extension, a context editing feature and a memory tool — which should make it easier to edit large chunks of data without getting rate limited (as in using up the context window too soon).
Looking good on benchmarks
The SWE-bench Verified has the Sonnet 4.5 model at 83% completed with tools, where GPT-5 only scores 72.8% and Gemini 2.5 Pro does 67.2% according to Anthropic.
Sonnet 4.5 also scores great on computer use, a metric they are so far alone in using, scoring 61.4% in OSWorld versus Sonnet 4 plain’s lead at 42.2% just four months ago.
It also beats every model out there in agentic coding, to tool usage and high school math, but gets beaten by GPT-5 in graduate-level reasoning, multilingual and visual reasoning. It does, however, stand out in financial analysis.
Can think for extended periods
Professioinals in finance, law, medicine and stem, find the model to be much better at knowledge in their fields, says Anthropic.
The model also breaks the previous production model record in reasoning time, having spent some thirty hours coding a chat app from scratch.
The model is live now on Claude, so you get to check it out yourselves.
As for pricing? It’s the same as for Sonnet 4 at $3 for a million input tokens and $15 for output tokens.
Read more: Anthropic’s launch page, writeups at Engadget, Ars Technica and The Verge. Discussion on r/Singularity