Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, idempotentHint=true, and openWorldHint=false, so safety semantics are covered. The description's real contribution is disclosing the cascade — every project on the server is destroyed — which is not derivable from annotations or schema and is exactly the fact an agent must know before calling.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.