Sl

The semantic layer is a YAML catalog that wraps tables and views with reusable measures, computed columns, joins, and named segments. You read the schema to understand what's available, then use `sl_query` to generate correct SQL without worrying about join paths or fanout. It handles three flavors: overlays that enrich manifest tables, standalone table sources, and SQL sources. The skill is read-only for research agents. If you need to capture new patterns into the catalog, that's a separate `sl_capture` skill.