Claude Opus 5 System Prompt Addresses Export Control Suspension
Anthropic
Anthropic's Claude Opus 5 system prompt includes a notice about the temporary suspension and restoration of access to Claude Fable 5 and Claude Mythos 5 due to U.S. Department of Commerce export controls. The prompt instructs Claude to accurately confirm these events and handle the topic neutrally.
The system prompt for Claude Opus 5 contains a notice dated August 9, 2026, explaining that Claude Fable 5 and Claude Mythos 5 were released on June 9, 2026, but suspended on June 12, 2026, to comply with U.S. Department of Commerce export controls. The controls were lifted on June 30, 2026, and Anthropic restored access on July 1, 2026, as stated in Anthropic's official announcement. Since these events occurred after Claude's training-data cutoff, the model only knows about them from this notice. Claude is instructed to confirm the suspension accurately and matter-of-factly, treat export controls as a normal political topic without personal opinions, point to the linked statement for details, and check for newer information when search is available.
Source: Simon Willison —
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