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Anthropic · AISep 15, 2026, 09:48 UTC

Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1

MajorNot disclosedUpdated 19h ago
Sep 15, 09:48 UTCSep 15, 11:14 UTC
Duration
1h 26m
Impact
Major
Root cause
Not disclosed
Anthropic, 90 days
94 incidents
Affected
claude.aiClaude API (api.anthropic.com)Claude CodeClaude Cowork
Status page

Final update

A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.

Timeline

  1. Resolved · Sep 15, 11:14 UTC
    A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.
  2. Monitoring · Sep 15, 10:50 UTC
    A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.
  3. Investigating · Sep 15, 09:52 UTC
    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.
  4. Investigating · Sep 15, 09:48 UTC
    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.

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Full history

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