Claude watermark guide
Zero-Width Character Checker
A zero-width character checker finds invisible Unicode controls and reports their exact code points and positions. It should not label those characters as a model-level Claude watermark.
What is checked
This checker looks for default-ignorable Unicode such as zero-width spaces, joiners, soft hyphens, variation selectors, and tag characters.
Safe interpretation
A finding establishes that the character exists. It does not establish who inserted it or why.
Check your Claude text
Inspect every detectable hidden character locally, then clean only the artifacts you select.
Check Text FreeSources
Published August 2026 · Updated September 1, 2026