Anthropic reported elevated errors across multiple Claude model families
Anthropic documented elevated request errors affecting several Claude Mythos, Fable and Opus versions on September 3. Most models recovered before Opus 4.8 and Opus 5, and the provider marked the incident resolved after roughly three hours.
- First observed
- Sep 3, 2026, 3:26:04 PM
- Disclosed
- Sep 3, 2026, 3:26:04 PM
- Status
- Resolved
- Confidence
- 99%
- Organization
- Anthropic
- Last reviewed
- Sep 4, 2026
Observed
Facts supported by sources
- Anthropic reported elevated errors affecting Claude Mythos 5.1, Fable 5.1, Mythos 5, Fable 5, Opus 5, Opus 4.8 and Opus 4.6.
- Anthropic reported that most models recovered first, then deployed a fix and said impact ended at 16:16 UTC on September 3.
Assessment
Interpretation, not observation
- Anthropic said it identified the cause but did not disclose that cause in the public status updates reviewed.
- The incident overlapped with outages at other AI providers, but no shared cause is established by the source.
Impact
Impact
Failed model requests across multiple Claude model families for affected API and product users.
Response
Response
Anthropic identified the cause, deployed a fix for the remaining models, monitored recovery and marked the incident resolved.