Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the nested poll fields (publish, poll_options, is_word_cloud, colors, etc.) are already fully documented. The description's only addition is restating the publish=true consequence and the default-draft behavior, which the schema partially covers. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.