● Covered by 2 sources · 2 reportsMedium impact2 negative
Anthropic's Claude AI Models Experience Elevated Error Rates, Affecting Multiple Services
Key points
- Elevated errors affected multiple Claude AI models.
- Incident began on September 3, 2026, around 9:41 AM ET.
- Affected models include Mythos/Fable 5.1, 5, Opus 5, 4.8, and 4.6.
- Services impacted: claude.ai, Claude API, Claude Code, Claude Cowork.
- Most models recovered; Opus 4.8 and Opus 5 still affected.
Outage Affects Claude AI Services
On September 3, 2026, several of Anthropic's Claude AI models began experiencing elevated error rates. The incident started around 9:41 AM ET and impacted users across various Claude services, including claude.ai, the Claude API, Claude Code, and Claude Cowork.
Affected Models Identified
Initially, Anthropic reported investigating elevated errors on Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. A subsequent update provided a more comprehensive list of affected models, which included Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, and Opus 4.6.
Cause Identified, Fix Underway
Anthropic identified the cause of the elevated errors and began working on a fix. As of the latest updates, most of the affected models have recovered to baseline error rates. However, Opus 4.8 and Opus 5 continue to experience elevated errors, and work on a full resolution is ongoing.
Impact on Users
The outage resulted in requests failing or returning errors for users relying on the affected Claude models. This disruption could impact workflows and access to Anthropic's AI capabilities for those utilizing these specific models and services.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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How outlets covered it
Anthropic's Claude AI models, including Mythos, Fable, and Opus versions, are experiencing an outage that began on September 3, 2026, at approximately 9:41 AM ET, causing elevated errors for users. This incident impacts users relying on these models for AI-powered applications and services, potentially disrupting workflows and access to Anthropic's latest AI capabilities.
Several Claude AI models, including Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, and Opus 4.6, experienced elevated error rates affecting claude.ai, Claude API, Claude Code, and Claude Cowork. The issue has been identified, and a fix is in progress, with most models now recovered except for Opus 4.8 and Opus 5.