Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. 'Delete' implies a mutation, but nothing is said about permanence/irreversibility, whether confirmation is needed, or what happens if the name doesn't exist — the key behavioral facts for a destructive operation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.