Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema covers 100% of the parameter, including examples and a clear note that it's a programme id, not a country name or website slug. The description reinforces the parameter by saying 'by id or all', which clarifies that id is optional. Since schema coverage is high, the description adds value by explaining the 'all' behavior, but the schema already has examples. Baseline is 3, and the description's clarification of the optionality and the 'or all' case earns a 4.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.