Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0% across five parameters, so the description must compensate. It mentions only two ('filename or ext') and implies they are alternate ways to supply the same value, but gives no meaning for 'file', 'input', or 'extension', leaving three of five parameters fully undocumented.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.