Does it generate new content?

No. It restates the sentences you supply. "Fuller" expands contractions and points out which sentences are thin, but it will not invent the missing detail — that is your writing to do.

Can I see exactly what changed?

Yes — the result is shown as a word-level diff, with additions and deletions marked, so you can check every change before accepting it.

Does it work without Chrome's AI?

Yes. The rule-based transforms (contraction expansion, filler removal, hedge trimming) are deterministic and available in every browser, offline.

Rewrite Text Online — Free Tone Changer, Nothing Uploaded

Rewrite your text as more formal, more casual or shorter, with every change shown as a diff before you accept it. Runs entirely in your browser.