Starting today, every word Claude writes is watermarked—even older models can’t escape it
The watermark is hidden in its word-choice patterns, without adding a single character
It survives copy and paste, and changing a few things may not remove it
New models released since August already have it, including Opus 5.5
Starting November 3, older models like Opus 4.6 and Sonnet 4.6 will get it too
Detection tools are currently available only to regulators and the media; educational institutions are also on the list
Ordinary people who pay to use Claude aren’t on the list
The watermark is hidden in its word-choice patterns, without adding a single character
It survives copy and paste, and changing a few things may not remove it
New models released since August already have it, including Opus 5.5
Starting November 3, older models like Opus 4.6 and Sonnet 4.6 will get it too
Detection tools are currently available only to regulators and the media; educational institutions are also on the list
Ordinary people who pay to use Claude aren’t on the list
