Cyber Security· Important
Anthropic cuts Claude distillation by 90-99% with new reasoning-protection defenses
Anthropic published details on how it curbed 'illicit distillation' — large-scale covert operations that scrape Claude's reasoning transcripts to train rival models cheaply. New measures, including reasoning summarization, 'preserved thinking' for new API accounts, and a two-stage classifier system, reportedly cut the volume of usable reasoning data extracted by distillers by 10-100x. Anthropic says a Chinese lab, Zhipu, used distillation (including attempts against Claude) to build GLM-5.3, which US assessors found to be the most cyber-capable open-weight model released so far with safeguards that are easily bypassed.