Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish the safe-read profile (readOnlyHint, idempotentHint, destructiveHint=false, closed-world), so the bar is lower. The description goes beyond them by specifying the returned fields and adding a real behavioral guarantee: unlinked or draft claims are never surfaced as citations, which tells the agent the output is filtered/verified rather than raw.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.