Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is already 100%, but the description adds significant meaning: it explains what each 'by' value means, clarifies defaults for role and by, and ties limit to the published top-15 dataset. It also specifies the output fields (afm, name, metric, total), surpassing what the schema alone conveys.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.