Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and idempotentHint=true, so safety and repeat-call behavior are covered structurally. The description adds genuinely non-obvious context beyond that: history is retained, the change is reversible only via crm_restore_contact, and there is a $0.001 per-call cost with no charge on failure. Only minor gaps remain, such as what happens to already-archived contacts or whether the contact stays readable via crm_get_contact.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.