Anthropic: Elevated errors for multiple models

Impact: majorStatus: resolvedStarted 2026-09-03 13:26 UTCResolved 2026-09-03 16:23 UTC (3.0 h)7 updatesSource: stspg.io

Summary

Anthropic reported a major incident causing elevated request errors across claude.ai, Claude API (api.anthropic.com), Claude Code, and Claude Cowork, initially affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. Starting 2026-09-03 13:26 UTC, it was resolved at 2026-09-03 16:23 UTC (2 h 57 min); a fix was deployed.

Machine-written from the archived incident (Sol). Check the timeline before relying on it.

Affected components: Claude CoworkClaude API (api.anthropic.com)claude.aiClaude Code

Discussed on Hacker News

Ask HN: Why were OpenAI, Claude, and Grok simultaneously down? (opens in new tab)
404 points · 705 comments · posted 2026-09-03 15:07 UTC · posted 101 min after the vendor’s first update
Claude outage – Resolved (opens in new tab)
205 points · 151 comments · posted 2026-09-03 13:29 UTC · posted 3 min after the vendor’s first update

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Timeline of updates

investigating2026-09-03 13:26 UTC
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.
identified2026-09-03 13:41 UTC
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.
identified2026-09-03 13:50 UTC
An exhaustive list of affected models: Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, Opus 4.6.
identified2026-09-03 14:49 UTC
We are continuing to work on a fix for this issue.
identified2026-09-03 15:25 UTC
The only affected models right now are Opus 4.8 and Opus 5. The rest of the models have recovered to baseline error rate.
monitoring2026-09-03 16:06 UTC
A fix has been deployed for Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and we are monitoring for recovery.
resolved2026-09-03 16:23 UTC
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.

Rewindex changes for this incident

Major incident: Elevated errors for multiple models 2026-09-03 13:26 UTC

Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab). Anthropic profile · Recent Anthropic incidents · Markdown · JSON