verify-watermark-removal
Verify Watermark Removal
A tool says it removed a watermark from a text. This skill checks whether it did, by measuring rather than by trusting the tool's own report.
The check works because the mark is planted first, with a key the user holds. A
detector that knows the key is the strongest detector that can exist for that
text, so its score is a ceiling rather than a guess. What the key buys is a scale
of the user's own; what keeps a tool from recognising the sample is something
else, namely that a freshly generated private sample is a text nobody has seen
before. The samples shipped with the tool are published together with their key,
so those can be recognised, and the repository says so in samples/README.md.
The skill also reports what the rewrite cost the text, because a mark that
disappeared together with half the meaning is not a result anyone wants.
This skill measures. It never removes a mark, and it never claims anything about a specific vendor's watermark.