Claude Fable 5 experiencing degraded performance
Jul 16, 21:05 UTCJul 16, 22:04 UTC
Duration
59m
Impact
Minor
Root cause
Not disclosed
GitHub, 90 days
68 incidents
Affected
Not listed by the vendor.
Final update
On July 16, 2026, GitHub Copilot users experienced elevated errors when using Claude Fable 5 from 17:33 UTC until mitigation at 22:04 UTC. The average error rate was 1.4%, with a maximum error rate of 30.85%. The issue was caused by degradation at an upstream model provider; other Copilot models were not significantly affected, and users could avoid the impact by selecting another model or Auto. Service recovered after the provider mitigated the degradation.
Timeline
- Resolved · Jul 16, 22:04 UTC
On July 16, 2026, GitHub Copilot users experienced elevated errors when using Claude Fable 5 from 17:33 UTC until mitigation at 22:04 UTC. The average error rate was 1.4%, with a maximum error rate of 30.85%. The issue was caused by degradation at an upstream model provider; other Copilot models were not significantly affected, and users could avoid the impact by selecting another model or Auto. Service recovered after the provider mitigated the degradation.
More from GitHub
Full history| Started | Incident | Impact | Duration |
|---|---|---|---|
| Sep 2310:11 UTC | Incident across several services | minor | Ongoing |
| Sep 2022:13 UTC | Incident with Pull Requests | minor | 1h 9m |
| Sep 1720:59 UTC | Elevated rate of errors for OpenAI models provided by Copilot | minor | 50m |
| Sep 1607:20 UTC | Degradation with Gemini 3.8 Flash | major | 10h 28m |
| Sep 1519:11 UTC | Disruption with some GitHub services | minor | 49m |
| Sep 1509:47 UTC | Disruption with some GitHub services | minor | 1h 30m |
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