Article 50 of the EU AI Act has entered into force. Enterprises running generative AI tools now have to comply with Article 50, which requires providers and deployers of certain AI systems to tell people when they’re interacting with a machine, and to mark AI-generated content so it can be flagged as such. Providers of systems generating synthetic audio, image, video, or text face a separate duty under Article 50. Marking is the mechanism. The output needs a machine-readable mark, detectable as artificially-generated or manipulated.