Major incident

Anthropic (Claude): Elevated errors for multiple models

Affected: claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork

Current status of Anthropic (Claude): Operational — live Anthropic (Claude) status

Timeline

1. Sep 3, 2026, 13:26 UTC
   investigating
   We are investigating elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. We will provide an update as soon as possible.
2. Sep 3, 2026, 13:41 UTC
   identified
   We have identified the cause of elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and are working on a fix. We will provide an update as soon as possible.
3. Sep 3, 2026, 13:50 UTC
   identified
   An exhaustive list of affected models: Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, Opus 4.6.
4. Sep 3, 2026, 14:49 UTC
   identified
   We are continuing to work on a fix for this issue.
5. Sep 3, 2026, 15:25 UTC
   identified
   The only affected models right now are Opus 4.8 and Opus 5. The rest of the models have recovered to baseline error rate.
6. Sep 3, 2026, 16:06 UTC
   monitoring
   A fix has been deployed for Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and we are monitoring for recovery.
7. Sep 3, 2026, 16:23 UTC
   resolved
   The issue affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 has been resolved. Impact has ended as of 9:16 PT / 16:16 UTC.

Updates as published by Anthropic (Claude) (original).