Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world). The description adds genuinely new context by disclosing the output shape — nodes and links for a network diagram, including relation kinds and frequency — which matters because there is no output schema. It still omits filtering/pagination behaviour and how the entity name is matched.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.