New feature will not be visible to humans and will remain in place even after text is cut-and-pasted.

This move is part of the company's effort to comply with the EU regulation and transparency requirements for AI.

Anthropic will embed machine-readable watermarks in all Claude model text outputs starting August 2, 2026, complying with the EU AI Act globally.

EU rules cited as reason for effort to trace AI output ancestry

Anthropic said new Claude models will embed an "imperceptible watermark" directly into AI-generated text.