Claude announces invisible watermarks for text

The article explains that invisible watermarks are the most robust form of marking, surviving edits, cropping, and screenshots. Google’s SynthID system, used by OpenAI and now by Claude, embeds a watermark at the pixel level for images and videos. For text, the watermark is hidden in the probability distribution of token choices, making it hard to detect without specialized tools.

While the EU mandate pushes companies like Anthropic, Meta, Microsoft, and Black Forest Labs to adopt watermarking, the article notes that xAI and Midjourney have not yet signed up. Detecting these watermarks requires different tools from each provider, and rewriting text can remove the watermark, limiting its effectiveness.