Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, but the description adds meaningful semantics beyond the schema: it clarifies that year is for historical tables from 2025+ and that omission returns the current table. This adds value, even though it leaves ambiguous behavior for years between 2000 and 2024 allowed by the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.