Anthropic watermarks Claude text for EU rules

Anthropic has confirmed it will embed watermarks in text generated by its AI models, including Claude, to comply with European regulations. The disclosure came via an updated support page, marking the company’s latest move to address growing pressure on AI firms to make machine-generated content identifiable.

EU transparency rules take effect

The EU AI Act’s Transparency Code, which took effect on August 2, requires AI companies to mark AI-generated or edited content in a way that other systems can identify. The regulation is part of the bloc’s broader effort to bring more accountability to the AI industry.

According to Anthropic, all models released after August 2 will automatically include technology to watermark both computer-generated text and files. For files, the company is using the C2PA open standard, a widely adopted technical specification for certifying the origin of digital content.

Older models to get support

Anthropic said it will extend watermarking support to older models as well. The company also emphasized that the watermark will travel with the text when users copy and paste it, meaning the marker is designed to persist beyond the original output.

“Because the watermark is part of the text, it will travel with the text when it’s copied and pasted elsewhere, and may persist through some editing. Watermarking will be applied at the model level, which means it will be present no matter which Claude product or surface the text comes from,” the support page reads.

— Anthropic support page

The company noted that watermarking will apply to different products, including the Claude platform API, Claude, Claude Code, Claude Cowork, and Claude Tag.

How the watermark works

Anthropic said the watermark is embedded at the model level, meaning it will be present regardless of which Claude product or interface generates the text. The company did not specify how much editing might be required to strip the watermark, and it has been asked for clarification.

Industry-wide push for watermarking

Anthropic’s move comes as platforms rush to watermark AI-generated content after backlash from users and to avoid regulatory scrutiny. Last week, AI music platform Suno said it will mark tracks created on its platform after a spate of legal challenges. Last month, newsletter service Substack teamed up with Pangram to flag AI-generated content, with CEO Chris Best calling out “Claudefishing,” a term for using AI to generate content.

EU code gains backers

Anthropic joins other companies such as Black Forest Labs, Google, Meta, Microsoft, OpenAI, and Synthesia in committing to adhere to the EU’s code. The growing list of signatories suggests broad industry alignment with the transparency requirements, though implementation details may vary across companies and products.

Why it matters for users

For businesses and individuals relying on Claude for content generation, the watermarking could add a layer of accountability. It may also affect how AI-generated material is used in contexts where transparency is expected, such as journalism, academic work, or legal documents. The persistence of the watermark through copy-paste and some editing means it could be difficult to fully remove, which could have implications for how AI-assisted work is perceived and verified.