keboola Using the Keboola semantic layer safely
The Keboola MCP system prompt already documents the semantic-layer workflow
(discover with search_semantic_context, inspect with get_semantic_context,
validate_semantic_query, then query_data). This skill adds the one failure
mode that workflow does not spell out.
The semantic layer already carries the physical mapping — use it, don't
bypass it. A semantic-dataset returns its tableId and fqn; a
semantic-metric returns its SQL. The business-facing display names (a field
labelled Total Revenue, an entity Trips) are not the physical columns —
they are labels on top of the definition. The failure is writing SQL from those
labels instead of from the definition the tools already gave you.
The one rule
Before you embed any SQL into app, transformation, or report code, confirm the
real column names against Keboola MCP — e.g. get_table on the dataset's
tableId — and use the metric's SQL verbatim rather than reinventing it. If
search_semantic_context returns nothing relevant, there is no model to
consult: say so and work against raw Storage. How you batch those checks is up
to you.
Worked example — the failure this skill prevents
A user asked Kai to build a dashboard from the semantic layer over
out.c-nyc-aggregations-duckdb.rpt_* tables. Kai read the semantic context but
wrote the dashboard SQL from the semantic display names, never confirming
the physical columns. They didn't match the rpt_* schema, so every query
failed: the dashboard rendered empty even though the container was "running",
and Kai reported success without verifying.
What grounds it instead:
search_semantic_context(patterns=["nyc trips", "daily revenue"])
→ metric "daily_revenue", dataset with tableId out.c-nyc-aggregations-duckdb.rpt_daily
get_semantic_context(...) → metric SQL + dataset tableId + fqn (the physical mapping)
get_table(table_id="out.c-nyc-aggregations-duckdb.rpt_daily")
→ real columns: pickup_date, fare_total, trip_count (NOT the display labels)
The label the user thinks in ("revenue") is the physical column fare_total;
the semantic definition tells you that — read it instead of guessing.
Related
dataapp-developmentskill — full app lifecycle; its../dataapp-development/references/storage-access.mdcovers FQN quoting per backend and../dataapp-development/references/dev-workflow.mdcovers the validate-first loop. Load this skill alongside it when the data source is a semantic model.