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 all four parameters (id, name, subject, body) with basic descriptions. The description adds no additional parameter semantics beyond what's in the schema - it doesn't explain parameter relationships, constraints, or usage examples. Baseline 3 is appropriate when schema does the heavy lifting.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.