This morning Anthropic launched Claude Sonnet 4.5, which they’re confidently calling “the best model in the world” for a wide range of tasks. We've just added it to Sudowrite.

For authors, Anthropic touts Sonnet 4.5’s “creative flair” and “first-try quality.” That translates to better-than-ever instruction-following, and polished, professional prose generation. It keeps the large 200K context window of its predecessor, meaning you’ll be able to max out your Chapter Continuity or build Plugins that can handle a full manuscript.

One caveat: This model just launched earlier today. We haven't put it through extensive testing yet, and can’t yet speak to how well it writes narrative fiction. (Should be a powerhouse for Plugins though!)

Claude Sonnet 4.5 is live now in Write, Draft, and Plugins. Give it a spin, and please let us know what you think of it!