Elevated errors for multiple models

Timeline

1. Sep 22, 2026, 2:35 AM UTC

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

2. Sep 22, 2026, 2:11 AM UTC

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

3. Sep 22, 2026, 1:35 AM UTC

   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. Sep 22, 2026, 1:17 AM UTC

   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.

5. Sep 22, 2026, 12:57 AM UTC

   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.