Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% — name, summary, and body_markdown are each documented in the schema. The description's phrase 'Optionally set the initial body as Markdown' is largely redundant with the schema's 'Optional Markdown body for the first draft.' Baseline 3 applies because the schema carries the parameter-documentation burden.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.