As AI-generated content proliferates across the internet — it surpassed human-written content recently — companies are taking steps so that people can tell it apart from human content. The company has published a breakdown of what this means in practice, and the short version is that Claude output is about to start carrying invisible fingerprints. Anthropic says marking will apply to output from supported models everywhere Claude is offered, worldwide, and across every surface — the API, Claude.ai, Claude Code, Cowork, and Tag. A detected mark only tells you that Claude may have processed the content at some point — it doesn’t confirm the full history of that content. For businesses building on top of Claude, Anthropic has flagged that the obligation doesn’t stop at the model layer.