Updated 9:21 a.m. Eastern on October 5, 2026
Claude reports elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. The incident is resolved, with impact from 05:40 PT / 12:40 UTC to 06:10 PT / 13:10 UTC.
What is affected
The incident affected requests to Claude Mythos 5.1 and Claude Fable 5.1, with listed components claude.ai, Claude API (api.anthropic.com), Claude Code, and Claude Cowork.
Official update timeline
We are investigating elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. We will provide an update as soon as possible.
The issue affecting Claude Mythos 5.1 and Claude Fable 5.1 has been resolved. Impact occurred from 05:40 PT / 12:40 UTC to 06:10 PT / 13:10 UTC.
