Elevated errors on Fable 5 due to upstream provider
This summary is created by Generative AI and may differ from the actual content.
Overview
On August 24th, 2026, between approximately 06:35 and 07:25 UTC, the Copilot service experienced degradation of the Claude Fable 5 model due to an issue with the upstream provider. Users encountered elevated error rates when using Claude Fable 5, with requests sometimes failing mid-response. No other models were impacted. The issue was resolved by a mitigation put in place by the upstream provider. GitHub is working with the provider to further improve the resiliency of the service to prevent similar incidents in the future.
Impact
Elevated error rates on Claude Fable 5 model in Copilot service, with requests sometimes failing mid-response. No other models were impacted.
Trigger
An issue with the upstream model provider caused degradation of the Claude Fable 5 model.
Detection
Degraded availability for the Fable model was detected and reported, leading to investigation at 07:12 UTC.
Resolution
The issue was resolved by a mitigation put in place by the upstream provider. During the incident, GitHub recommended users choose another model or select 'Auto' to continue using Copilot as a workaround.
Root Cause
An issue with the upstream model provider caused the degradation of the Claude Fable 5 model. GitHub is collaborating with the provider to further improve the resiliency of the service to prevent similar incidents in the future.