Disruption with OpenAI Models

Lesson: Reliance on external AI models can lead to service disruptions if those models experience issues.

What happened

On May 28th, 2026, between approximately 18:27 and 20:41 UTC, the GitHub Copilot service was degraded due to an issue with the Responses API of an upstream provider affecting the GPT-5.2, GPT-5.3-Codex, GPT-5.4, and GPT-5.5 models. Requests routed to these models via the Responses API returned elevated error rates, which also affected Copilot coding agent and Copilot code review. No other models were impacted. We mitigated the incident by shifting traffic away from the affected models while the upstream provider deployed a fix. GitHub is working to improve automated failover for the affected models and strengthen monitoring to prevent similar incidents in the future.

1. Resolved · May 28, 20:41 UTC
   On May 28th, 2026, between approximately 18:27 and 20:41 UTC, the GitHub Copilot service was degraded due to an issue with the Responses API of an upstream provider affecting the GPT-5.2, GPT-5.3-Codex, GPT-5.4, and GPT-5.5 models. Requests routed to these models via the Responses API returned elevated error rates, which also affected Copilot coding agent and Copilot code review. No other models were impacted. We mitigated the incident by shifting traffic away from the affected models while the upstream provider deployed a fix. GitHub is working to improve automated failover for the affected models and strengthen monitoring to prevent similar incidents in the future.