Anthropic shares more details about how Claude’s new watermarks will work

Anthropic published a blog post Friday seeking to answer some basic questions about how it will watermark the text generated by its chatbot Claude. Such as: How will the watermarking actually work? Can it be hidden with editing? And how does this affect code?

Claude users have been debating the move since the company revealed earlier this week that it would be doing this watermarking to comply with the EU AI Act’s Transparency Code, which requires AI companies to use systems that make it possible to identify AI-generated content.

On Reddit, for example, one poster characterized this as a conspiracy against innocent Claude users, while another claimed, “The only reason you wouldn’t want this is to lie to people.” And Business Insider reports that “dozens” of users on X have claimed to cancel their Claude subscriptions as a result.

Anthropic’s new post starts with a general overview of the watermarking concept, explaining that when making “low-stakes choices” — like choosing between the words “overcast” and “grey” to describe the weather — Claude can create a pattern in its responses that is “undetectable to the reader, but is detectable to anyone who has a key that encodes it.”

“Watermarking does not impact the quality of Claude’s output,” the company said. “To a reader, a watermarked response is indistinguishable from an unwatermarked one.”