Elevated errors for multiple models

Final update

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.

1. Resolved · Sep 3, 16:23 UTC
   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.
2. Monitoring · Sep 3, 16:06 UTC
   A fix has been deployed for Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and we are monitoring for recovery.
3. Identified · Sep 3, 15:25 UTC
   The only affected models right now are Opus 4.8 and Opus 5. The rest of the models have recovered to baseline error rate.
4. Identified · Sep 3, 14:49 UTC
   We are continuing to work on a fix for this issue.
5. Identified · Sep 3, 13:50 UTC
   An exhaustive list of affected models: Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, Opus 4.6.
6. Identified · Sep 3, 13:41 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.
7. Investigating · Sep 3, 13:26 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.