Live

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.

The latest update from Anthropic.

State

Resolved

Started

47 d ago

2026-09-15 09:48 UTC

Lasted

1 h 26 min

until 2026-09-15 11:14 UTC

Worst impact

Partial outage

Timeline

4 updates
09:4810:0910:3110:5311:14
Partial outageUpdate postedTimes in UTC

Investigating

1 h 2 min 72%

Monitoring

24 min 28%

Updates

Times in UTC

As posted by Anthropic

Resolved2026-09-15 11:14 UTC

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.

Monitoring2026-09-15 10:50 UTC

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.

Investigating2026-09-15 09:52 UTC

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.

Investigating2026-09-15 09:48 UTC

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.

Affected components

4
claude.aiClaude API (api.anthropic.com)Claude CodeClaude Cowork

Anthropic in the last 90 days

Full history
90 days agoToday

Incidents in 90 days

50

Days with an incident

42

Median duration

1 h 8 min

This incident

1.3× the median

How long each incident lasted, on the day it started. The outlined bar is this incident.

6 days
median 1 h 8 min
90 days agoToday

Other Anthropic incidents

All incidents

Follow Anthropic

Your coding agent knows when Anthropic is down, and tells you when a failure is theirs, not yours. You can also get Anthropic incidents in a feed reader or in Slack.

Prompt
Install the outages.live MCP server, so that when something breaks you can tell if the cause is a provider we depend on and not my code. It reads the official status pages of cloud, AI, payment and developer providers and gives you their incidents as MCP tools.

Add it as a remote MCP server named "outages" at https://outages.cc/mcp (Streamable HTTP, no authentication), with your CLI command or your MCP config file.

Then:
1. Make sure it connects and shows the tools get_provider, list_feed and send_feedback.
2. Call get_provider with "anthropic" and tell me if Anthropic has a problem right now.
3. From now on, when a call to a third-party service fails or becomes slow, call get_provider for that service before you change my code.

Paste this into any coding agent. It adds the server with its own MCP setup.

RSS
https://outages.cc/feed.xml?providers=anthropic
Slack
/feed subscribe https://outages.cc/feed.xml?providers=anthropic

FAQ

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