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

Affected components

• Claude API (api.anthropic.com)
• Claude Code
• Claude Cowork
• claude.ai

1. resolvedAug 13, 2026, 16:08 UTC

   The issue affecting Claude Mythos 5 and Claude Fable 5 has been resolved.

2. investigatingAug 13, 2026, 15:44 UTC

   We are investigating elevated errors on requests to Claude Mythos 5 and Claude Fable 5. We will provide an update as soon as possible.

3. investigatingAug 13, 2026, 14:33 UTC

   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.

What APIStatus.watch saw

Our 5-minute checks didn't record a change in Anthropic's overall status around this incident. Smaller or regional incidents often leave a provider's overall status green.

Other services with incidents at the same time

Overlapping incidents aren't necessarily related.

• Grafana Cloud: K6 Test OutageCritical · Aug 13, 2026, 15:25 UTC
• Elasticsearch: Increased error rates for microsoft-multilingual-e5-largeMajor · Aug 13, 2026, 08:32 UTC
• Cursor: Investigating service degradation — Automations, Cloud Agents, and IDEMajor · Aug 13, 2026, 14:46 UTC
• Akamai: Certificate Provisioning System (CPS) IssuesMinor · Aug 11, 2026, 10:11 UTC
• GitHub: Errors with the Fable 5 Model in CopilotMinor · Aug 13, 2026, 14:43 UTC
• GitHub: Incident with WebhooksMinor · Aug 13, 2026, 14:45 UTC

How often does Anthropic have incidents?

Anthropic reported 47 incidents in the last 90 days, 21 of them major or critical. A typical incident lasted 1h 4m. See Anthropic's uptime and incident history