Disruption with Copilot for access to some models
This summary is created by Generative AI and may differ from the actual content.
Overview
GitHub Copilot users experienced an incomplete list of available models between 19:48 UTC and 20:49 UTC on August 10, 2026. During this 61-minute window, the service returned as few as one model instead of the full catalog. Requests attempting to use models missing from the shortened list failed with "model not found" errors. The issue was caused by a change to how model data was published that systems could not read back correctly, causing fallback to a limited default list. The incident was mitigated by 20:49 UTC and a fix was deployed by 21:50 UTC. Data-residency (Proxima) environments were not affected.
Impact
Users were unable to access the full catalog of available models in GitHub Copilot. Requests using unavailable models failed with "model not found" errors. Copilot requests using available models were not affected. The impact was limited to standard environments, with no impact to data-residency (Proxima) environments.
Trigger
A change to how model data was published that caused systems to be unable to read the data correctly, resulting in fallback to a limited default list containing only one model instead of the full catalog.
Detection
Users reported issues accessing certain models. Monitoring detected degraded performance for some GitHub services at 20:27 UTC, followed by reports of impacted Copilot model access at 20:39 UTC.
Resolution
The incident was mitigated by 20:49 UTC by addressing the model data publication issue. A fix was deployed by 21:50 UTC to prevent immediate recurrence. Additional validation and retry safeguards were added to verify model data before serving it to users.
Root Cause
A change to how model data was published that the systems could not read back correctly, causing the service to fall back to a limited default list instead of serving the complete model catalog.