Past incident

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

Anthropic · Critical · Started

Duration
Unavailable
Severity
Critical
Status
No longer listed as active

Summary

Critical · No longer listed as active

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

View official incident ↗

Event timeline

How this incident unfolded, from the official status page.

  1. Investigating

    Anthropic

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

  2. Identified

    Anthropic

    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.

  3. Monitoring

    Anthropic

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