Maintain

Keep the repository correct as the world underneath it moves, on both of its axes: the dbt project and the semantic layer. Maintenance is the recurring half of the loop: warehouses drift, loads half-fail, models go stale, keys stop being unique, and business definitions change. This skill compares a known-good baseline against current reality, classifies what drifted, and proposes the reconciling edit. It is manual and on-demand here; continuous drift detection and automated PRs are the commercial product.

The model: baseline, detect, reconcile

Drift is measured against a baseline (the .dex/snapshot.json fingerprint of the warehouse map and the repository's per-layer definitions). Detection is read-only; only reconcile proposes edits.