GitHub Outage Postmortem: The August 17, 2026 Incident and What It Teaches Us About AI Agent Reliability
On August 17, 2026, GitHub suffered a 7-hour-and-47-minute outage that took down Issues, Pull Requests, the API, Actions, and Copilot, with peak web and API error rates around 20% and archive downloads failing roughly half the time. The root cause was a single misconfigured autoscaling policy on an Istio sidecar that cascaded through load balancers, the authentication path, and client retry logic into a platform-wide failure. This postmortem breaks down exactly what happened, why retry storms amplified the damage tenfold, and what the incident teaches operators about building reliable systems in the age of AI agents. ...