The introduction of the Observation framework has refined SwiftUI’s state reactivity from the object level down to the property level, significantly reducing many unnecessary view computations caused by coarse-grained observation. I recently explored and implemented Observation support in Core Data Evolution, giving `NSManagedObject` property-level precise observation capabilities. This article discusses the motivation behind this feature, how to use it, its implementation approach, the engineering challenges involved, and some of the trade-offs made during development.