Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the transparency burden; it does communicate the core behavior and mechanism: control-point positions are averaged to smooth selected objects. It omits side-effect information, supported object types, reversibility, and selection preconditions, which matter for a mutating tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.