Methods, systems, and computer-readable media related to a technique for combining two or more aspects of predictive information for auto-completion of user input, in particular, user commands directed to an intelligent digital assistant. Specifically, predictive information based on (1) usage frequency, (2) usage recency, and (3) semantic information encapsulated in an ontology (e.g., a network of domains) implemented by the digital assistant, are integrated in a balanced and sensible way within a unified framework, such that a consistent ranking of all completion candidates across all domains may be achieved. Auto-completions are selected and presented based on the unified ranking of all completion candidates.