Elevated errors for Claude Fable 5.1, Sonnet 5.5, and Haiku 5.5
critical- Started
- Oct 23, 7:37 PM EDT
- Resolved
- Oct 23, 8:11 PM EDT
- Duration
- 34 min
Anthropic's updates (4)
- investigating · Oct 23, 7:37 PM EDT
We are investigating elevated errors on requests to Claude Fable 5.1. We will provide an update as soon as possible.
- identified · Oct 23, 7:39 PM EDT
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.
- monitoring · Oct 23, 7:54 PM EDT
We are seeing success rates return to normal for all affected models, and are continuing to monitor to ensure no further issues.
- resolved · Oct 23, 8:11 PM EDT
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.
What our checks recorded
We checked Claude 7 times from Anthropic's start time to its resolution, once every five minutes. Every one of them reached Claude's site, so this incident did not show up as a failed page load. Our check loads the public site; it cannot see an API error or a broken feature. Median response time was 241 ms, against 195 ms over the 24 hours before. Anthropic posted the incident at Oct 23, 7:37 PM EDT.
Updates are Anthropic's own words from its status page (status: resolved); we never add an inferred cause. The vendor's incident page ↗