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 restates the point and polygon shape plus the 3+ coordinate requirement, but the schema already documents the LatLon fields, required minimum, and automatic closure. The description adds minimal semantic value beyond the structured schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.