---
id: "INC-anthropic-6304r9jjhj34"
kind: "incident"
aliases: []
title: "Anthropic: Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1"
severity: "high"
cvss: null
epss: null
exploited: false
status: "resolved"
category: "vendor"
products: [{"name": "Anthropic", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["ai", "anthropic", "incident", "llm", "ops", "vendor"]
not_affected_if: []
published_at: "2026-09-15T09:48:23+00:00"
first_seen_at: "2026-10-23T19:12:22+00:00"
updated_at: "2026-10-23T21:50:49+00:00"
sources: [{"source": "statuspage", "url": "https://stspg.io/x1qpycpg6ln7", "first_seen_at": "2026-10-23T19:12:22+00:00"}]
---

# Anthropic: Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1

## Affected

- vendor:Anthropic affected ? fixed ?

## Timeline

- 2026-10-23T19:12:22+00:00 statuspage https://stspg.io/x1qpycpg6ln7

## From the sources

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.

---

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