Claude watermarks your code now

Claude's text watermark is designed to travel with generated text when it is copied elsewhere. Anthropic's documentation says supported models embed the mark across products, including Claude Code, and that it may survive some editing.

Detection provides a limited provenance signal. Anthropic describes detection as a private preview for eligible organizations. Claude may have processed material whose underlying content came from someone else, and short or heavily edited passages may not retain a detectable mark. A positive result therefore suggests possible Claude involvement without establishing the complete authorship history; a negative result cannot establish that a passage was written entirely by a person.