Anthropic incident: Degraded performance for multiple models

Affected components

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

1. resolvedAug 18, 2026, 19:01 UTC

   The issue affecting Claude Opus 5 has been resolved. Impact occurred from 16:11 to 18:23 UTC.

2. monitoringAug 18, 2026, 18:26 UTC

   A fix has been implemented and we are monitoring the results.

3. investigatingAug 18, 2026, 17:12 UTC

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

4. investigatingAug 18, 2026, 16:20 UTC

   We are investigating elevated errors on requests to Claude Mythos 5, Claude Fable 5, Claude Opus 5, Claude Sonnet 5, Claude Haiku 4.5, and other Claude models. We will provide an update as soon as possible.

5. investigatingAug 18, 2026, 16:20 UTC

   We are investigating reports of degraded performance affecting multiple models. 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.

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• Akamai: Connection drops and increased latency in MiamiMinor · Aug 13, 2026, 19:31 UTC
• Supabase: 401 errors due to JWT rejectionsMinor · Aug 14, 2026, 02:23 UTC
• Telnyx: Programmable Wireless data loss in AustraliaMinor · Aug 17, 2026, 19:27 UTC
• Twilio: SMS Delivery Delays from Twilio to Free Caraibe FranceMinor · Aug 18, 2026, 00:33 UTC
• Twilio: SMS Delivery Delays and Failures from Twilio Phone Numbers to Claro BrazilMinor · Aug 18, 2026, 14:30 UTC
• Twilio: Voice Call Failures from T-Mobile United States to a Subset of Twilio United States Phone NumbersMinor · Aug 18, 2026, 14:56 UTC
• Expo: iOS Submissions hanging on App Store Connect build uploadsMinor · Aug 18, 2026, 16:25 UTC
• Twilio: Flex login errors with SSOv2Minor · Aug 18, 2026, 17:10 UTC
• Twilio: 1Console Login UnavailableMinor · Aug 18, 2026, 17:13 UTC

How often does Anthropic have incidents?

Anthropic reported 85 incidents in the last 90 days, 32 of them major or critical. A typical incident lasted 1h 7m. See Anthropic's uptime and incident history