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

Anthropic Claude

1. 23 Oct 23:54 UTCMonitoringWe are seeing success rates return to normal for all affected models, and are continuing to monitor to ensure no further issues.
2. 23 Oct 23:39 UTCIdentifiedWe 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. 23 Oct 23:37 UTCInvestigatingWe are investigating elevated errors on requests to Claude Fable 5.1. We will provide an update as soon as possible.

1. 23 Oct 2026 · 23:55:15 UTC StageIdentified → Monitoring
2. 23 Oct 2026 · 23:55:15 UTC SummaryWe 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. → We are seeing success rates return to normal for all affected models, and are continuing to monitor to ensure no further issues.

The most recent 100 field changes are listed. Complete recorded revisions are kept separately.

Cite this recorded revision to keep the same title, summary, facts and links when the page changes.

A day selects the latest observation by the end of that UTC day; today's selection can change until midnight. History starts when this installation records it.

• Service status now: every provider ChangeIntel reads, with ongoing incidents first.
• Status RSS feed: new and ended incidents as they happen.
• Everything about Anthropic Claude: its changes, known issues and incidents on one timeline.