Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the baseline is 3. The description earns above baseline by giving concrete examples ('Mercury', `context`: "planet orbit") and by clarifying that `type` uses the same topic id that `fetch` names as `topic:…`, cross-linking the two params' semantics.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.