Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false. The description adds genuinely new context: the deletion is irreversible ('cannot be undone') and requires user confirmation before executing. It does not cover auth/permission requirements or failure modes, keeping it short of a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.