Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema describes only 'iban' as a string with zero description coverage, so the description must compensate. It names the content of the parameter implicitly ('validate an IBAN'), but it does not specify expected formatting (spaces, uppercase, country prefix) or acceptable variants. It adds some but not full meaning beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.