How Claude's text watermarking works

Anthropic is preparing to release an API that allows third parties to detect if text was generated or edited by Claude. The system utilizes Google’s SynthID technology to embed an invisible watermark by subtly adjusting word selection patterns during generation. This approach ensures the mark persists even when human users modify the output. The tool addresses the growing challenge of identifying machine-generated content, though Anthropic notes that the detection method has limitations when applied to factual or short-form writing.