Anthropic adds AI text watermarking to Claude models worldwide

Anthropic said it will begin embedding machine-readable watermarks into text generated by new Claude AI models worldwide. This fulfills commitments the company made under the European Union’s AI Act transparency code.

EU rules, global rollout. The new requirements apply to Claude models launched in the EU on or after Aug. 2. Anthropic said it will enable the watermarking system everywhere Claude is available, not just in Europe.

• Watermarking will cover output from supported models across Claude, the Claude API, Claude Code, Claude Cowork and Claude Tag.
• Anthropic is also working to add watermarking to models released before Aug. 2 during the AI Act’s transition period.

Invisible marks in text. When a supported Claude model generates text, it embeds an imperceptible, machine-readable watermark into the response. Anthropic said the watermark does not change the meaning, quality or readability of the text.

• Because the watermark is embedded in the text itself, it stays with the content when it is copied and pasted. It may also survive some editing.
• Watermarking happens at the model level, so it is included regardless of which Claude product generated the output.
• Supported PNG, JPG and SVG files will also receive signed C2PA provenance metadata.

Yes, but. Anthropic said it will provide tools for users and third parties to detect embedded text watermarks and signed provenance metadata. Technical documentation will be released later. The company also cautioned that a detected watermark only shows that the content may have been processed by Claude.

• It doesn’t prove Claude created the original ideas or wrote the original text.
• Likewise, the absence of a detectable watermark doesn’t mean content wasn’t AI-generated.
• Older models, heavily edited text, and files with stripped metadata may not contain detectable marks.

Why we care. Claude is widely used to create, edit, and refine marketing content. Anthropic said the watermarks are intended to improve transparency. If AI text watermarking becomes more common, it could change how AI-generated content is identified and disclosed.

Claude’s support page. How Claude marks AI-generated content