Claude AI Faces Outage Impacting Mythos 5.1, Fable 5.1, and Opus 5
Brief
Anthropic’s Claude AI experienced a partial outage on September 3, 2026, disrupting requests across several Claude models and affecting developers, enterprise users, and individuals relying on the platform for coding, research, writing, and creative work.
The incident began to draw attention at around 9:40 AM EDT, when users reported elevated error rates, stalled responses, and failed requests across Claude’s web service and API.
Anthropic confirmed the disruption through its public status page, initially reporting that it was investigating elevated errors involving Claude Mythos 5. 1, Claude Fable 5. 1, and Claude Opus 5. The company later said it had identified the underlying cause and was working on a fix. A subsequent update expanded the list of affected models to include Mythos/Fable 5. 1, Mythos/Fable 5, Opus 5, Opus 4. 8, and Opus 4.
6.