Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0% across 5 parameters including two nested image objects, so the description has to carry weight. It does clarify the crucial mutual exclusivity the schema cannot express (images in ChatGPT vs. the two asset IDs in Codex, 'use one method, not both'), but it never explains the consent field, nor why download_url and file_id are jointly required.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.