Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents amount, api_key, and the deprecated connected_account_id. The description reinforces the destination rule ('never a caller-supplied one'), which matches rather than extends the schema's own note, so baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.