# Claude: Major incident: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5

**Summary:** Claude reported a major incident involving 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; the resolution update named Mythos 5 and Fable 5. _(machine-written, sol)_
- Kind: Major incident · Label: outage (model (Jev))
- Changed: 2026-08-13 14:33 UTC · Detected: 2026-10-17 18:22 UTC
- [Source: https://stspg.io/pbnrks0mrn4w](https://stspg.io/pbnrks0mrn4w)
- [Company: Claude](https://rewindex.com/company/claude.md)
- Versions: before (none: first archived) → after incident\_version:6/j160kkjmm2n1@2bacf8e6f3c6
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-08-13 14:33 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-08-13 16:08 UTC
```

**6. Added: Affected components**

```diff
+ claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork
```

**7. Added: Update** (investigating) · 2026-08-13 14:33 UTC

```diff
+ 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.
```

**8. Added: Update** (investigating) · 2026-08-13 15:44 UTC

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

**9. Added: Update** (resolved) · 2026-08-13 16:08 UTC

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

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-08-13 14:33 UTC | Major incident: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5 (this change) | outage |

All Claude changes: [timeline](https://rewindex.com/company/claude/changes.md)
_Diff excerpts are shown on normalized text: dates, counters and tokens appear as ‹date›, ‹count›, ‹tok›; noise-only edits are hidden. Rewindex shows the changed passages, not a copy of the page._


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Canonical: https://rewindex.com/change/i1e3d07b0a3e2e4 · Markdown: https://rewindex.com/change/i1e3d07b0a3e2e4.md · JSON: https://rewindex.com/api/v1/changes/i1e3d07b0a3e2e4 · Generated 2026-10-18T02:55:14.469Z