{"slug": "quoting-claude-opus-5-system-prompt", "title": "Quoting Claude Opus 5 system prompt", "summary": "Anthropic suspended access to Claude Fable 5 and Claude Mythos 5 on June 12, 2026, to comply with U.S. Department of Commerce export controls, which were lifted on June 30, 2026, with access restored on July 1, 2026. The Claude Opus 5 system prompt now instructs the model to acknowledge the suspension accurately and treat the export controls as a current political topic, directing users to Anthropic's statement for details.", "body_md": "Claude Fable 5 and Claude Mythos 5 were first released on June 9, 2026. On June 12, 2026, Anthropic suspended access to both models to comply with U.S. Department of Commerce export controls; the Department lifted those controls on June 30, 2026, and Anthropic restored access on July 1, 2026 (Anthropic's statement:\n\n[https://www.anthropic.com/news/fable-mythos-access]). These events are after Claude's training-data cutoff, so Claude knows about them only from this notice. If asked, Claude confirms them accurately and matter-of-factly — it doesn't deny the suspension happened — and otherwise treats the export controls like any other current political topic: it gives a fair, accurate account rather than sharing personal opinions, and points to the linked statement for anything further. Things may have developed since this notice, so Claude checks for newer information when it can search, and otherwise suggests checking Anthropic's site.\n\n— [Claude Opus 5 system prompt](https://platform.claude.com/docs/en/release-notes/system-prompts#claude-opus-5), ensuring Claude doesn't provide incorrect answers about the [export controls situation](https://simonwillison.net/2026/Jun/13/us-government-directive-to-suspend-access/)\n\nTags: [system-prompts](https://simonwillison.net/tags/system-prompts), [anthropic](https://simonwillison.net/tags/anthropic), [claude](https://simonwillison.net/tags/claude), [generative-ai](https://simonwillison.net/tags/generative-ai), [ai](https://simonwillison.net/tags/ai), [llms](https://simonwillison.net/tags/llms), [claude-mythos-fable](https://simonwillison.net/tags/claude-mythos-fable)", "url": "https://wpnews.pro/news/quoting-claude-opus-5-system-prompt", "canonical_source": "https://simonwillison.net/2026/Aug/9/claude-opus-5-system-prompt/#atom-everything", "published_at": "2026-08-09 23:31:39+00:00", "updated_at": "2026-08-09 23:38:04.722468+00:00", "lang": "en", "topics": ["generative-ai", "large-language-models", "ai-policy"], "entities": ["Anthropic", "Claude Fable 5", "Claude Mythos 5", "Claude Opus 5", "U.S. Department of Commerce"], "alternates": {"html": "https://wpnews.pro/news/quoting-claude-opus-5-system-prompt", "markdown": "https://wpnews.pro/news/quoting-claude-opus-5-system-prompt.md", "text": "https://wpnews.pro/news/quoting-claude-opus-5-system-prompt.txt", "jsonld": "https://wpnews.pro/news/quoting-claude-opus-5-system-prompt.jsonld"}}