Get Notebook Cost Overview

A chart query response: its descriptor plus a chart-shaped result.

columns is list[ChartColumn], not list[ColumnDescriptor] — a chart plots values, it never renders a table, so it does not carry the table-only affordances (sortable/filterable/edit/link/...) a ColumnDescriptor has. meta is ChartMeta, not DatasetMeta, for the same reason: see that class's docstring for why pagination and dataset fields do not belong here.

A summary response: just its metrics.

No meta: every field on DatasetMeta is a TABLE concept. row_count is always 1, and total/page/size/pages/prev/next are always null — a summary has no pagination to describe, because there is nothing to page through. Emitting them invited a client to write pagination handling for an endpoint that can never have any. The dataset name is already known to the caller: it is in the URL they requested.