Anthropic is weaving an invisible, machine-readable watermark into every word its newest Claude models write—and it hasn't said how.

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.

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

The EU’s AI rules are having an impact.

Anthropic has complied with Europe's rules.