Anthropic to Charge for Rejected Requests to Prevent Distillation Attacks
Distillation attacks are the reason Anthropic has started billing again for some requests Claude refuses before answering. From 24 September 2026, blocked requests in three categories, bio, frontier_llm and reasoning_extraction, are charged at the refusing model’s input rates. This article explains what each category covers, the 114 days when refusals were free, what a billed block costs and what developers should change.
