Changes / Anthropic / Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5

Anthropic: Major incident: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5

Summary

Anthropic reported a major incident with elevated request errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5, affecting claude.ai, Claude API (api.anthropic.com), Claude Code, and Claude Cowork. It started at 2026-08-13 14:33 UTC and was resolved at 2026-08-13 16:08 UTC, lasting 1 h 34 min; no cause or fix was stated.

Machine-written from the diff below (Sol; type: incident outage). Check the diff before relying on it.

Major incidentLabel: outage (model (Jev), 94%)Changed Detected Source: stspg.io

What changed

AddedTitle#1
Before: not present
After: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5
AddedImpact#2
Before: not present
After: major
AddedStatus#3
Before: not present
After: resolved
AddedStart time#4
Before: not present
After: 2026-08-13 14:33 UTC
AddedResolved time#5
Before: not present
After: 2026-08-13 16:08 UTC
AddedAffected components#6
Before: not present
After: claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork
AddedUpdateinvestigating#7
Before: not present
After: We are investigating elevated errors on requests to Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5. We will provide an update as soon as possible.
AddedUpdateinvestigating#8
Before: not present
After: We are investigating elevated errors on requests to Claude Mythos 5 and Claude Fable 5. We will provide an update as soon as possible.
AddedUpdateresolved#9
Before: not present
After: The issue affecting Claude Mythos 5 and Claude Fable 5 has been resolved.

First version of this incident archived by Rewindex. View the live incident.

History of this incident

When (UTC)ChangeKind
Major incident: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5 (this change)
Anthropic reported a major incident with elevated request errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5, affecting claude.ai, Claude API (api.anthropic.com), Claude Code, and Claude Cowork. It started at 2026-08-13 14:33 UTC and was resolved at 2026-08-13 16:08 UTC, lasting 1 h 34 min; no cause or fix was stated.
Major incident

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