Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The only parameter, 'format', is fully described in the schema with an enum (text/json), a default value, and a clear description 'Output format', giving 100% schema coverage. The tool description does not add any extra parametric context, but since the schema fully explains the parameter, the baseline of 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.