Cloud-based AI models operated by Open AI, Anthropic, x AI, and Google suffered a rare and overlapping set of significant service interruptions over a period of hours Thursday morning. Anthropic first reported a partial outage related to elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 at 9:23 am Eastern. The company identified the cause roughly 15 minutes later and deployed a fix, resolving the issue by 12:16 pm.

A separate incident involving Claude Sonnet 5 occurred just after noon. OpenAI reported elevated errors across ChatGPT and Codex resulting in degraded performance starting at 10:43 am, with a mitigation resolving the issue by 12:55 pm. As of this writing, xAI's Grok currently displays a user-facing error message that the model is experiencing issues and the company is working on restoring service.

User-submitted reports from DownDetector regarding Grok surged from less than 10 just before 9 am to 1,365 by 9:45 am and have since fallen to 273.