Anthropic models will soon inject watermarks identifying AI-generated text

Anthropic said in a support document Tuesday that its future AI models will embed invisible watermarks in all text to identify AI-generated content, starting with Claude models released after August 2, 2026. The move responds to the EU AI Act's Article 50(2) Code of Practice on Transparency, which Anthropic has signed, and will apply globally. Anthropic will also add provenance data to images, video, and audio using the C2PA standard to satisfy California's AI transparency law.

Anthropic said in a support document https://support.claude.com/en/articles/16266773-how-claude-marks-ai-generated-content Tuesday that its future AI https://www.fastcompany.com/section/artificial-intelligence models will put an invisible watermark in all text, identifying it as AI-generated. The change comes in response to new AI transparency laws in the EU, but Anthropic says it will apply in all countries where Claude models are used. No U.S. law currently requires AI-generated content to carry transparency disclosures or watermarks, although a growing number of states, California among them, have enacted AI transparency laws with labeling requirements. In the support document, Anthropic says it has signed the EU AI Act’s Article 50 2 Code of Practice on Transparency of AI-Generated Content https://digital-strategy.ec.europa.eu/en/policies/code-practice-ai-generated-content , which includes watermarking provisions, and explains how it plans to put those rules into practice. Claude models released after August 2, 2026, will generate watermarks within text at launch, Anthropic explained. Under EU law, AI providers will have until December 2, 2026 about four months , to upgrade earlier or existing models to support the machine-readable marking requirement. Anthropic isn’t giving away too much information about how it will add the watermarks to the text, but it says the watermark will “travel with the text when it’s copied and pasted elsewhere.” More details will be included in “forthcoming technical documentation,” the company says. The models will also inject standard provenance data into generated images, video, and audio. That part of the plan will satisfy the requirements of California’s AI transparency law. Anthropic will use the Coalition for Content Provenance and Authenticity C2PA https://c2pa.org/ standard. According to the European Commission’s signatory list, about 190 companies and organizations had signed the Code of Practice on Transparency by the end of July 2026. Other than Anthropic, signatories include OpenAI, Google, Microsoft, Amazon, Mistral, Cohere, and others. Conspicuously absent are Elon Musk’s xAI and Mark Zuckerberg’s Meta.