Give us pasted text, a Word document or an image, and this page says precisely what happens: which marks come off, what comes back, and what we will put our name to.
Three kinds of input, three kinds of mark. The columns are the marks, explained mark by mark on how it works.
More file types are coming soon.
The confident claims above are only worth something because of these.
Text and files are processed, returned and deleted. Uploads are held only for the length of the request, and nothing you paste is kept.
Anthropic’s public detector is not open yet, so today nobody can check a text watermark, us included. Until it opens, we hand you measurements and say exactly what they are.
Anthropic has committed to a detection API anyone can use. From the day it opens we run our own output against it, and if the rewrite ever fails that check, this page says so and that part stops being sold.
Paste text or drop a file, and see what it is carrying. No account needed.