Claude Watermark

What is Claude Watermark?

Anthropic is watermarking Claude's text. Tools selling "watermark removal" strip invisible Unicode — which cannot touch that mark, because it is distributional: a secret key biases word choice, so the watermark IS the wording. Paste text and see, in your browser, every fingerprint a detector actually finds: the HTML classes copy-paste leaves behind (what the AO3 Claude detector checks), zero-width characters, odd spaces, stylistic tells. Nothing is uploaded. One button then cleans those artifacts and rewrites the prose in two passes. Free to check. 10 credits on signup, no card.

Key features

• Check any text for detectable AI artifacts in your browser
• Finds zero-width characters, odd spacing and stylistic tells
• One-click cleaning that rewrites the prose in two passes
• Nothing uploaded — checks run locally, free with no card