Anthropic just released Claude Fable 5.1, an upgrade to their flagship Fable model. We've added it to Sudowrite.

Fable 5 has been a recent favorite among Sudowrite authors, and 5.1 is a refinement of that same flagship. Anthropic points to performance gains and (notably for authors) fewer false refusals. In plain terms: 5.1 should be even less likely to balk at legitimate story content—dark themes, violence, heat—so your prose can go wherever the story needs to go.

In testing, it was nominally cheaper to use than Fable in the Write button, whereas Draft credit usage is basically identical. We haven't put it through its paces on long-form fiction just yet, so we can’t fully attest to its prose. Maybe you’ll let us know what you think?

Claude Fable 5.1 is available now in Write, Draft, and Plugins.