No official affiliation
Independent tool. Not affiliated with or endorsed by Anthropic. Claude is a trademark of Anthropic PBC. The use of the Claude name identifies the subject of the utility and does not imply sponsorship, approval, or partnership.
No official watermark verification
Anthropic has announced model-level text watermarking for supported Claude models, but an official third-party detection method is not publicly available at this time. The official result card therefore shows “Not publicly verifiable yet.” The site does not calculate a Claude probability score or infer authorship from sentence length, vocabulary, hidden characters, or formatting.
Hidden characters are not proof
Zero-width characters, Unicode spaces, bidirectional controls, joiners, variation selectors, tags, and other formatting can have legitimate origins. A finding should be reviewed in context. Removing one does not prove that a model-level mark was removed.
Cleanup can change meaning or display
Joiners and direction controls can be necessary for complex scripts. Variation selectors and tags can be necessary for emoji and glyph presentation. Protected defaults and previews reduce risk but cannot cover every format. Keep an original copy and review the result.
Rewriting is editing, not verification
Rewriting changes wording but does not prove or guarantee removal of any model-level watermark or AI-detection signal. Rewritten output can contain errors or lose nuance. Review facts, citations, code, data, quotations, and formatting before use.
Trademark notice
Claude is a trademark of Anthropic PBC. Other names and marks belong to their respective owners.