Claude Status · History · Incident #137055

RESOLVED

Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1

Major · Started Sep 15, 2026 · 9:48 AM

Duration

1h 26m
Severity

Major
Detection lead

—
User reports

Peak 3/hr

Summary

Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1

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.

Started

Sep 15, 2026 · 9:48 AM
Resolved

Sep 15, 2026 · 11:14 AM
Duration

1h 26m
Severity

Major

Event timeline

How this incident unfolded

◐

Investigating
Sep 15 · 9:48 AM Claude

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.
◐

Investigating
Sep 15 · 9:52 AM Claude

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.
◉

Monitoring
Sep 15 · 10:50 AM Claude

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.
✓

Resolved
Sep 15 · 11:14 AM Claude

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.

User reports · incident window

Report volume over time

Hourly report count. Red bars mark the incident window.

Peak: 3 reports/hr

← Before incident After →

Pattern

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