Errors with the Fable 5 Model in Copilot

Final update

On August 13th, 2026, between approximately 14:06 and 15:47 UTC, the Copilot service experienced a degradation of the Claude Fable 5 model due to an issue with our upstream provider. Users encountered elevated error rates, peaking at 43% and averaging 12%. Users who selected Auto or alternative models were unaffected. The issue was resolved by a mitigation put in place by our provider. GitHub is working with our provider to further improve the resiliency of the service to prevent similar incidents in the future.

1. Resolved · Aug 13, 15:47 UTC
   On August 13th, 2026, between approximately 14:06 and 15:47 UTC, the Copilot service experienced a degradation of the Claude Fable 5 model due to an issue with our upstream provider. Users encountered elevated error rates, peaking at 43% and averaging 12%. Users who selected Auto or alternative models were unaffected. The issue was resolved by a mitigation put in place by our provider. GitHub is working with our provider to further improve the resiliency of the service to prevent similar incidents in the future.
2. Investigating · Aug 13, 15:47 UTC
   The issues with our upstream model provider have been resolved, and Fable 5 is once again available in Copilot products and IDE surfaces. We will continue monitoring to ensure stability, but mitigation is complete.
3. Investigating · Aug 13, 15:23 UTC
   We are seeing modest recovery, but are still experiencing degraded availability for the Fable 5 model in Copilot products and IDE surfaces. This is due to an issue with an upstream model provider. While we work with them to resolve the issue, we recommend choosing another model or selecting 'Auto' to continue using Copilot.
4. Investigating · Aug 13, 14:50 UTC
   We are experiencing degraded availability for the Fable 5 model in Copilot products and IDE surfaces. This is due to an issue with an upstream model provider. While we work with them to resolve the issue, we recommend choosing another model or selecting 'Auto' to continue using Copilot.
5. Investigating · Aug 13, 14:43 UTC
   We are investigating reports of degraded performance for Copilot AI Model Providers