# Elevated errors for multiple models

- Provider: [Anthropic](https://down.guide/anthropic)
- Level: confirmed
- Impact: Partial outage
- lasted 2h 57m
- started 2026-09-03 13:26 UTC
- claude.ai, Claude API (api.anthropic.com), Claude Code +1
- id: DWN-66864c34c6
- Official page: https://stspg.io/9xz4hhmd1jzn

## Updates from Anthropic
### 2026-09-03 13:26 UTC: investigating
We are investigating elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. We will provide an update as soon as possible.

### 2026-09-03 13:41 UTC: identified
We have identified the cause of elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and are working on a fix. We will provide an update as soon as possible.

### 2026-09-03 13:50 UTC: identified
An exhaustive list of affected models: Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, Opus 4.6.

### 2026-09-03 14:49 UTC: identified
We are continuing to work on a fix for this issue.

### 2026-09-03 15:25 UTC: identified
The only affected models right now are Opus 4.8 and Opus 5. The rest of the models have recovered to baseline error rate.

### 2026-09-03 16:06 UTC: monitoring
A fix has been deployed for Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and we are monitoring for recovery.

### 2026-09-03 16:23 UTC: resolved
The issue affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 has been resolved. Impact has ended as of 9:16 PT / 16:16 UTC.

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