Anthropic has signed the EU AI Act’s Article 50(2) Code of Practice on Transparency of AI-Generated Content and is implementing that commitment in its models. Claude models launched on or after August 2, 2026 embed a machine-readable mark in generated output: text receives an imperceptible watermark, while supported generated files receive cryptographically signed provenance metadata.
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This is not an EU-only feature or a Claude chat-app feature. It applies worldwide to supported output from the Claude Platform API, Claude, Claude Code, Claude Cowork, and Claude Tag. If your backend calls the Claude API, the text returned by the model carries that mark, as does output you pass on to users.
For teams building APIs around Claude, this affects model selection, file-processing pipelines, disclosure design, and automated tests. This guide explains what gets marked, what marks can prove, and which checks to add to your CI pipeline. If you test AI-backed endpoints, Apidog can run those checks on every build.
The short version
