Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the baseline is 3; the description goes slightly further by giving a concrete interpretation of age_range ('0-4' for products that injure young children most), which explains what narrowing means in practice rather than just restating the enum.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.