Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The single parameter 'tsn' is fully described in the input schema with type, description, and examples. The description reiterates 'Taxonomic Serial Number, e.g. 180582', adding no new semantics beyond what the schema provides. With 100% schema coverage, baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.