Incident

Updates

1. investigating Sep 22, 2026, 8:57 AM GMT+08:00

   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. identified Sep 22, 2026, 9:17 AM GMT+08:00

   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. identified Sep 22, 2026, 9:35 AM GMT+08:00

   We are continuing to work to resolve errors affecting some models. At this time, requests to Claude Fable 5 and 5.1 and Mythos 5 and 5.1 have returned to normal success rates. We are working to resolve remaining errors affecting Claude Opus 5, and will provide an additional update shortly.

4. monitoring Sep 22, 2026, 10:11 AM GMT+08:00

   We have seen success rates return to normal across affected models, and are monitoring closely to ensure no further issues.

5. resolved Sep 22, 2026, 10:35 AM GMT+08:00

   This issue has been resolved. Impact occurred from 5:50pm PT / 00:50 UTC to 7:10pm PT / 02:10 UTC.