maintain

Use this to keep a dbt project correct as the warehouse and the business change. It detects drift on four axes and proposes the fix: schema drift (source columns and tables added, dropped, retyped, or renamed), volume drift (a row count that collapsed, a table that emptied, a load that half-failed), grain drift (a key that lost uniqueness, a changed row-per-entity cardinality, an increased join fanout), and semantic drift (a metric, measure, dimension, or entity definition that no longer matches, new categorical values, dangling semantic references). Reach for this when something that used to work has started failing or producing different numbers and the cause is more likely upstream than in the code you just wrote: a test that began failing with no code change, a dashboard whose numbers moved, a model that is suddenly empty or duplicated. Trigger it for requests like "what changed in the warehouse", "did anything drift", "is my dbt project still in sync", "my primary key has duplicates now", "the row count dropped", "did the load run", "the data stopped flowing", "the revenue metric definition changed", "reconcile my models with the source schema", or "which models are stale". It reads the .dex/ snapshot and proposes reviewable diffs; it never overwrites hand-written work. To author new models or metrics from scratch, use transform. To learn an unfamiliar warehouse for the first time, use explore.