Elevated errors for Claude Fable 5.1, Sonnet 5.5, and Haiku 5.5

resolved

The issue affecting Claude models has been resolved. Impact occurred from 16:28 PT / 23:28 UTC on October 23 to 16:59 PT / 23:59 UTC on October 23.

10/24/2026, 12:11:20 AM

monitoring

We are seeing success rates return to normal for all affected models, and are continuing to monitor to ensure no further issues.

10/23/2026, 11:54:14 PM

identified

We have identified the cause of elevated errors on requests to Claude Fable 5.1, Sonnet 5.5, and Haiku 5.5, as well as fast mode requests to Opus 5.5 and are working on a fix. We will provide an update as soon as possible.

10/23/2026, 11:39:22 PM

investigating

We are investigating elevated errors on requests to Claude Fable 5.1. We will provide an update as soon as possible.

10/23/2026, 11:37:42 PM