Designs, reviews, and hardens Kimball-style dimensional models - star schemas, conformed dimensions, bus matrix, slowly changing dimensions. Use when modeling analytical data for a warehouse, lakehouse, or BI semantic layer - declaring a fact table's grain, deciding whether something is a fact or a dimension attribute, picking an SCD type for an attribute that changes, or drafting the bus matrix that makes cross-process reporting reconcile. MUST be used whenever star-schema DDL, a dbt mart, or a model spec is reviewed or handed to an ETL team, because mixed grains, nullable foreign keys and a type 2 dimension keyed on its business key are cheap to catch there and expensiv…
