Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so length limits, empty-string-clears semantics, and omit-to-keep behavior are already documented in the schema. The description restates the same constraints rather than adding syntax or format detail beyond it, so baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.