What's the concern? Harness tends to be fairly common in the context of "shim program which manages some other program" (see: "test harness", "fuzzing harness", etc.)
It’s just a fancy way of saying scaffolding.
It's kinda ironic that everything has become an "app" over the past 10 years. Facebook is an "app", Reddit is an "app", your bank is an "app". However, the one time we actually introduce an app to execute our LLM calls, we don't call it an "app"? Wat.