Anthropic to Add Invisible Watermarks to All Claude AI Outputs
Brief
Anthropic has announced plans to add invisible watermarks and signed metadata to content created by Claude AI. The move follows the company’s decision to sign the European Union AI Act’s Article 50(2) Code of Practice on Transparency of AI-Generated Content .
The system is designed to help people identify content that may have been generated or processed by Claude. Claude models launched in the European Union on or after August 2, 2026, will support machine-readable marking from their release date.
Anthropic said the marking system will apply globally, not only in Europe. It will cover supported Claude models used through the Claude website, API platform, Claude Code, Claude Cowork , Claude Tag, and cloud-based services.
The company will use 2 separate marking methods. The first method is an invisible watermark embedded directly into AI-generated text.