# Anthropic: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1

- Impact (vendor’s label): major
- Status: resolved
- Started: 2026-10-05 13:05 UTC · Resolved: 2026-10-05 13:21 UTC · Duration: 16 min
- Updates: 2 · Affected components: Claude Cowork, Claude API (api.anthropic.com), claude.ai, Claude Code
- [Vendor status page: https://stspg.io/wdqhxt8xt574](https://stspg.io/wdqhxt8xt574)
- [Company: Anthropic](https://rewindex.com/company/anthropic.md)

## Summary

Anthropic reported a major incident with elevated errors for Claude Mythos 5.1 and Claude Fable 5.1 across claude.ai, Claude API (api.anthropic.com), Claude Code and Claude Cowork. It started 2026-10-05 13:05 UTC and resolved at 2026-10-05 13:21 UTC (computed duration: 15 min); the vendor reported impact from 12:40 UTC to 13:10 UTC. _(machine-written, sol)_
## Timeline of updates

- **investigating** 2026-10-05 13:05 UTC: We are investigating elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. We will provide an update as soon as possible.
- **resolved** 2026-10-05 13:21 UTC: The issue affecting Claude Mythos 5.1 and Claude Fable 5.1 has been resolved. Impact occurred from 05:40 PT / 12:40 UTC to 06:10 PT / 13:10 UTC.

## Rewindex changes for this incident

- 2026-10-05 13:05 UTC: [Major incident: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1](https://rewindex.com/change/i9edd8c4e3e4216.md)


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Canonical: https://rewindex.com/company/anthropic/incidents/bhphxz3vr58g · Markdown: https://rewindex.com/company/anthropic/incidents/bhphxz3vr58g.md · JSON: https://rewindex.com/api/v1/companies/anthropic/incidents/bhphxz3vr58g · Generated 2026-10-18T11:45:10.929Z