Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the behavioral disclosure burden. It adds useful constraints ('limit max 500', official API, allowed intervals), but does not disclose ordering, default values, return shape, or whether the operation is explicitly read-only.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.