Anthropic adds invisible watermark to Claude AI text output

Every piece of text that Claude generates is about to carry a hidden signature. Anthropic announced Monday that Claude models released on or after August 2, 2026, will embed an imperceptible, machine-readable watermark directly into all generated text, invisible to human readers but detectable by the right tools. The watermark leaves the meaning and readability of the text completely intact. It survives copy-paste operations and holds up through at least moderate editing, which is exactly the point: the goal is to keep the signal alive even after the text has moved around the internet a few times. How it actually works The watermark is woven into the statistical patterns of the text, the subtle choices in word selection and phrasing that a language model makes billions of times per output. Humans cannot see it. Machines, with the right detection tool, can. Anthropic will also implement digitally signed provenance metadata built on the C2PA standard, a technical framework already used to verify the origin of images and video. Public detection tools will be released alongside the feature, though Anthropic is being measured about what they can actually promise. The watermark’s reliabi...