Resolved Anthropic (Claude) · degraded service

Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1

Posted 11 Sep 14:19 UTC, last seen today 14:09 UTC.

Anthropic (Claude) status page On the status board

Unknown Duration: the provider stated no start

5Updates posted

2Other incidents at the same time

What it affected

As the provider names it

claude.ai Claude API (api.anthropic.com)Claude Code Claude Cowork

What the provider posted

Newest first

11 Sep 14:37 UTCResolvedThe issue affecting Claude services has been resolved. Impact occurred from 13:57 to 14:20 UTC
11 Sep 14:28 UTCUpdateA fix has been deployed for the issue affecting Claude services and we are monitoring for recovery.
11 Sep 14:28 UTCMonitoringA fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring for recovery.
11 Sep 14:21 UTCIdentifiedWe have identified the cause of elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1 and are working on a fix. We will provide an update as soon as possible.
11 Sep 14:19 UTCInvestigatingWe are investigating elevated errors on requests to Claude Fable 5.1 and Claude Mythos 5.1. We will provide an update as soon as possible.

Around it

From the sources ChangeIntel reads; a match in time is not a cause

Elsewhere at the same time

Cloudflare Hyperdrive Degraded Performance
Anthropic (Claude) Degraded functionality for Claude Cowork on Windows

Earlier incidents in the 14 days before

Anthropic (Claude): Elevated latency on the Claude API for some usersService incident · 10 Sep
Anthropic (Claude): Elevated errors for multiple modelsService incident · 3 Sep
Anthropic (Claude): Elevated errors for Claude Sonnet 5Service incident · 2 times, latest 3 Sep
Anthropic (Claude): Delays in credit purchasesService incident · 1 Sep
Anthropic (Claude): Degraded performance on platform.claude.com and Claude for Microsoft Office 365Service incident · 1 Sep

What changed

First observed 14 Oct 2026

No field changes in the recorded history.

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Keep track

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