Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the description only needs to add context. It adds domain-scope semantics (no approval of wording/cause/timeline/workaround), which is useful, but says nothing about what creation returns, permissions, or side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.