Most uptime tools answer the same question. They tell you "is service X up?" from one vantage point — the monitoring server. But in a hybrid cloud, "up" is not a property of a service. It's a property of a path.

The problem: "up" depends on where you're standing

A single-server monitor (Uptime Kuma, Pingdom, etc.) checks SQL-01 from itself. If it says UP, you assume everyone can reach it. But your real topology looks like this:

SQL-01 (on-prem)

FuncApp-01 (VNet-A) ❌ DOWN