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 goes beyond the schema by decoding the track letters (A tolerance, B beta-cell restoration, C graft protection, D combination, E immunogenetics), which the schema does not explain at all — a real semantic gain for the most consequential parameter.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.