Within four hours of Anthropic confirming that Claude models would embed invisible watermarks into any AI-generated content, developer Guillaume Meyer had published his override. Since then, his code has gone viral on GitHub and garnered over 20,000 bookmarks on X, with many more contributing to the project.

Meyer and others started investigating how watermarking works after Anthropic announced it would adopt the practice in order to comply with the European Union’s AI Act. Some users are trying to evade the watermarking because they disagree with the idea that all AI-generated content should be labeled as such, while others simply relish the technical challenge.

The new rules stipulate that model providers like Anthropic and OpenAI must label synthetic audio, image, video, or text so that this material can be detected by a machine as AI-generated—or face fines of up to 3 percent of annual turnover. While the rules say providers cannot market circumvention tools, there is no legal restriction on independent tools.

Meyer’s removal method uses a non-watermarking large language model to generate multiple rewrites, swapping in synonyms and slightly reorganizing content. Wayne Pan, chief technology and cofounder at Haimaker, incorporated Meyer's open-source tool into his platform because he similarly disliked the idea of Claude watermarking content even when it has only been lightly edited.

Other coders have developed their own removal tools: Software engineer Erik Hughes took 15 minutes to knock up a tool with Claude that removes invisible and look-alike characters, reorders sentences within paragraphs, and swaps several words for synonyms. Leon Chlon, a Visiting Fellow at the University of Oxford, says the watermarks can be removed by condensing Claude’s response, translating it into a dialect like Arabic, which has very different semantics compared to English, and then translating it back.