Elevated errors for multiple models

Updates

• 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.

  Sep 3, 2026, 4:23 PM 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.

  Sep 3, 2026, 4:06 PM 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.

  Sep 3, 2026, 3:25 PM UTC

• identified

  We are continuing to work on a fix for this issue.

  Sep 3, 2026, 2:49 PM UTC

• identified

  An exhaustive list of affected models: Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, Opus 4.6.

  Sep 3, 2026, 1:50 PM 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.

  Sep 3, 2026, 1:41 PM 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.

  Sep 3, 2026, 1:26 PM UTC