Anthropic Cuts Claude Reasoning Token Theft by Up to 99% in Distillation Crackdown

Anthropic says it has cut stolen Claude reasoning tokens by up to 99% — a direct countermeasure against industrial-scale model distillation. The company confirmed the drop in a statement published Sunday, citing new detection systems and access restrictions that now block internal chain-of-thought outputs from being scraped at scale. Attackers had been using hundreds of thousands of fake accounts to extract those tokens, feeding them into rival models.

Anthropic names Zhipu and Moonshot as two Chinese firms involved: Zhipu allegedly used the data to train GLM-5.3’s cyber capabilities. Moonshot is accused of routing queries through Claude without disclosure. Both models are commercially available in China and globally. Anthropic warns stolen reasoning steps could feed into foreign military or surveillance tools, not just commercial AI.

So it’s now banning flagged accounts automatically. Tens of thousands have already been blocked. A classifier scans for extraction patterns in real time. And internal reasoning.