You can now choose the writing style you want Claude to use.

In addition to the default styles you see above, you can also specify your own writing style, either by describing it to Claude (this is similar to using custom instructions)…

Or by uploading examples of the style you want Claude to emulate.

And again, I’m going to say that ‘writing with AI’ isn’t something we’re going to be thinking about in the near future, in the same way we don’t think about ‘writing with a word-processor’ today.
We will assume that digital artefacts – whether text, audio, image, or video – will all have an AI fingerprint. In fact, it’s far more likely that we’ll see notices informing us when AI was not used in the creation, for those times when we want something produced entirely ‘by hand’.