Anthropic will watermark Claude's text. Anthropic also says paraphrasing removes it.
A provenance mark that survives copy-paste and dies to a rewrite is not a lie detector. It is a courtesy that honest people will trip and dishonest people will strip.
"Claude models launched on or after August 2, 2026 automatically weave an imperceptible, machine-readable watermark directly into generated text." [SOURCE ↗]
THE MOVE: ZERO UNDERNEATH, the headline number has nothing behind it
THE CLAIM. every Claude model launched on or after August 2 now weaves an invisible, machine-readable watermark into the text it writes, so AI content can be detected.
THE CHECK. read Anthropic's own help page. The mark may vanish if the text is 'heavily edited, paraphrased, translated, or mixed into other writing', or if the passage is short. There are zero published detection-accuracy or false-positive numbers, and the third-party detector is 'forthcoming'.
THE TWIST. the mark only shows Claude 'had a hand' in something, not that Claude wrote it. So it cannot clear a human who used Claude lightly, and it cannot catch a cheat who runs one paraphrase pass. It is real, it is default, and it solves the easy half of the problem while the hard half strips it in one step.
On August 11, 2026, Anthropic said every Claude model launched on or after August 2 now embeds an invisible, machine-readable watermark directly into the text it generates. It is applied at the model level, so it rides along everywhere Claude runs: the app, the API, Claude Code, and the cloud partne
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