Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the baseline would be 3. The description earns above baseline by explaining the no-comma American convention and illustrating accepted input strings ('+150', '62%', '2.5'), which clarifies the number-or-string typing in the schema. It does not, however, add anything not already implied about the range or enum semantics of `format`.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.