Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so safety and repeat-call behavior are covered structurally. The description adds useful scope context ('a card's two fields') and caller restriction, but says nothing about how next_card_id affects the mutation or what happens to fields not supplied.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.