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

Impact: majorStatus: resolvedStarted 2026-08-13 14:33 UTCResolved 2026-08-13 16:08 UTC (1.6 h)3 updatesSource: stspg.io

Summary

Anthropic reported a major incident with elevated request errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5, affecting claude.ai, Claude API (api.anthropic.com), Claude Code, and Claude Cowork. It started at 2026-08-13 14:33 UTC and was resolved at 2026-08-13 16:08 UTC, lasting 1 h 34 min; no cause or fix was stated.

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

Timeline of updates

investigating2026-08-13 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.
investigating2026-08-13 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.
resolved2026-08-13 16:08 UTC
The issue affecting Claude Mythos 5 and Claude Fable 5 has been resolved.

Rewindex changes for this incident

Major incident: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5 2026-08-13 14:33 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