Changes / Anthropic / Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1
Anthropic: Major incident: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1
Summary
Anthropic reported a major incident with elevated errors for Claude Mythos 5.1 and Claude Fable 5.1 across claude.ai, Claude API (api.anthropic.com), Claude Code and Claude Cowork. It started 2026-10-05 13:05 UTC and resolved at 2026-10-05 13:21 UTC (computed duration: 15 min); the vendor reported impact from 12:40 UTC to 13:10 UTC.
Machine-written from the diff below (Sol; type: incident outage). Check the diff before relying on it.
What changed
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After: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1
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After: major
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After: resolved
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After: 2026-10-05 13:05 UTC
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After: 2026-10-05 13:21 UTC
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After: claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork
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After: 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.
Before: not present
After: 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.
First version of this incident archived by Rewindex. View the live incident.
History of this incident
| When (UTC) | Change | Kind |
|---|---|---|
| Major incident: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1 (this change) Anthropic reported a major incident with elevated errors for Claude Mythos 5.1 and Claude Fable 5.1 across claude.ai, Claude API (api.anthropic.com), Claude Code and Claude Cowork. It started 2026-10-05 13:05 UTC and resolved at 2026-10-05 13:21 UTC (computed duration: 15 min); the vendor reported impact from 12:40 UTC to 13:10 UTC. | Major incident |
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