Disruption with some GitHub services
Incident
Report for GitHub
Resolved
On April 22, 2026 from 18:49 to 19:32 UTC , the Copilot Cloud Agent service began failing during session execution for users running the Agent HQ Codex agent. Codex agent sessions failed to start for all entry points (issue assignment, @copilot comment mentions). 0.5% of total Copilot Cloud Agent jobs were impacted (~2,000 failed jobs). Copilot and other agent sessions were unaffected.
This was caused by a model resolution mismatch in Codex agent sessions, resulting in an incompatible model being used at runtime. A mitigation was deployed to select a stable default model for Codex agent sessions.
We are working to harden the underlying model-resolution path so it correctly scopes to the requesting agent's supported models to prevent similar failure mode in the future.
This was caused by a model resolution mismatch in Codex agent sessions, resulting in an incompatible model being used at runtime. A mitigation was deployed to select a stable default model for Codex agent sessions.
We are working to harden the underlying model-resolution path so it correctly scopes to the requesting agent's supported models to prevent similar failure mode in the future.
Monitoring
The degradation has been mitigated. We are monitoring to ensure stability.
Update
We've found the issue and are working on deploying a solution to get Codex agent runs working again.
Update
Copilot Cloud Agent (CCA) jobs using the Codex agent are failing after starting. To avoid this issue, please choose a different agent. We are investigating the cause and working towards remediation
Investigating
We are investigating reports of impacted performance for some GitHub services.
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