Citipati likely ate both plants and animals. They helped to solidify the link between birds and dinosaurs, as many skeletons have been discovered in a “brooding” position, sitting atop a nest with arms spread around it, a behavior that is found in modern birds. The arms, likely covered in feathers, would protect and hide the eggs in the nest.
While Citipati and other oviraptorids may indeed have eaten other dinosaurs’ eggs, the original association with egg stealing was due to a misunderstanding. Initial remains of Oviraptor were found with eggs near Protoceratops, an early ceratopsian. The eggs were believed to belong to Protoceratops, but later fossilized embryos of Citipati found inside fossil eggs showed that the original eggs probably belonged to Oviraptor, not Protoceratops.