Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses that the entity acts autonomously and persists without intervention, but omits whether the call mutates state, what side effects occur, and whether the advancement is reversible or time-limited beyond the schema's default.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.