Free tool · Local text inspection
Claude Watermark Checker
Inspect text for hidden Unicode, formatting anomalies, sample suitability and Claude watermark verification status.
Runs locally · No account required · No text storage
Paste text to inspect
Your text is analyzed locally in your browser for the currently available checks.
Analysis results
How to read the result
Inspect text integrity without overstating provenance
Start with the official verification status. When it is unavailable, the rest of the report is a local integrity inspection: it can reveal hidden Unicode and explain sample structure, but it cannot identify a human or AI author.
- Paste a representative passage and run the local analysis.
- Review every unusual character in context before removing it; some are legitimate language or formatting characters.
- Use the cleaned-copy preview only when you have confirmed that the selected invisible characters are unwanted.
Frequently asked questions
Clear boundaries for a privacy-first local inspection.
Can this tool verify an official Claude watermark?
No. Claude text-watermark verification is not available through this tool because no supported official verification provider is configured. The result clearly reports that limitation rather than inferring authorship from writing style or hidden characters.
Does hidden Unicode prove that text came from Claude?
No. Zero-width characters, non-breaking spaces, bidirectional controls, and variation selectors can come from copy-paste workflows, editors, languages, accessibility tools, or malicious manipulation. They are inspection signals, not proof of source or authorship.
Does my pasted text leave my browser?
No. The scanner, counts, suitability heuristic, cleaning preview, and copy action run in your browser. This page has no text-analysis API endpoint and does not store pasted content.
What does sample suitability mean?
It is a transparent structural heuristic based on length, prose continuity, repetition, and code-like content. It only indicates whether text could be useful to inspect if an official statistical method becomes available; it is not a watermark result.