Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% (blockId is described), so baseline is 3. The description adds extra value by explaining how to obtain a valid blockId (from a trip record, with the full chain from arrivals), which is not fully captured in the schema description.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.