美国政府对 Anthropic Fable 5 和 Mythos 5 下达出口管制指令
Statement on the US government directive to suspend access to Fable 5 and Mythos 5
美国政府以国家安全为由，要求 Anthropic 暂停所有外国国民（包括外籍员工）对 Fable 5 和 Mythos 5 的访问。Anthropic 被迫全面禁用这两个模型，其他模型不受影响。政府声称发现了一种绕过 Fable 5 的方法，但 Anthropic 审查后确认该漏洞规模极小且非通用，其他公开模型（如 OpenAI GPT-5.5）也能发现相同漏洞，属于已知的次要缺陷。政府仅提供口头证据，未说明具体国家安全关切。Anthropic 表示将在24小时内公布更多细节。
The US government, citing national security authorities, has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States, including foreign national Anthropic employees. The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance. Access to all other Anthropic models****will not be affected.
We received the directive from the government today at 5:21pm (ET). The letter did not provide specific details of its national security concern. Our understanding is that the government believes it has become aware of a method of bypassing, or "jailbreaking" Fable 5. We reviewed a demonstration of this specific technique being used to identify a small number of previously known, minor vulnerabilities. These vulnerabilities all appear relatively simple, and we have found that other publicly-available models are able to discover them as well without requiring a bypass. [...]
To date, the government has only given us verbal evidence of a potential narrow, non-universal jailbreak, which essentially consists of asking the model to read a specific codebase and fix any software flaws. Our understanding is that one potential jailbreak was shared with the government. We have reviewed the report and validated that the level of capability displayed there is widely available from other models (including OpenAI's GPT-5.5), and is used every day by the defenders who keep systems safe. We will share more details over the next 24 hours.
I still have access to Fable via claude.ai and Claude Code now, at 9:01pm ET.
Update: I ran this script against the Anthropic API to spot when claude-fable-5 would stop working. My access was cut off at 6:59pm Pacific (9:59pm ET):
[2026-06-12T18:56:50-07:00] attempt 35: running uv run llm -m claude-fable-5 hi [2026-06-12T18:56:55-07:00] success: Hi there! How can I help you today? [2026-06-12T18:57:55-07:00] attempt 36: running uv run llm -m claude-fable-5 hi [2026-06-12T18:57:59-07:00] success: Hi! How can I help you today? [2026-06-12T18:58:59-07:00] attempt 37: running uv run llm -m claude-fable-5 hi [2026-06-12T18:59:00-07:00] FAILED after attempt 37 with exit code 1
stderr: Error: Error code: 404 - {'type': 'error', 'error': {'type': 'not_found_error', 'message': 'Claude Fable 5 is not available. Please use Opus 4.8. Learn more: https://www.anthropic.com/news/fable-mythos-access'}, 'request_id': 'req_011CbzRyirV7KZLHYYdBM9od'}
Posted 13th June 2026 at 1:01 am
来源：Simon Willison 博客 · simonwillison.net