Quoting Claude Opus 5 system prompt

According to Simon Willison's Weblog, an excerpt from Claude Opus 5's system prompt has come to light, revealing how Anthropic instructs its model to address export control events. The system prompt documents a brief suspension of Claude Fable 5 and Mythos 5 on June 12th, imposed due to U.S. Department of Commerce export controls, and their subsequent restoration on July 1st after restrictions were lifted. Per the prompt, Claude is directed to acknowledge these events accurately and treat export policy like other political topics — providing factual accounts without personal opinions.

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