Anthropic· ClaudeCapability change

How Claude’s text watermark works

Anthropic announces that future Claude models will include a text watermark to comply with the EU AI Act, using a method based on SynthID-Text that does not affect output quality, readability, or cost, and is undetectable to readers.

From the source

Future Claude models will generate text that contains a watermark. This is a way of determining the likelihood that Claude was involved in writing the text, and we, along with several other major AI providers, are implementing this change to comply with the EU AI Act.

anthropic.com