Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the full behavioral load. It usefully discloses the blocking semantics implied by 'Sleep' and the 0.01–60 second range that the schema does not encode, but it omits what happens on out-of-range values (clamp, error, or silent acceptance) and does not say whether the call blocks the workflow. No return-value detail is needed because an output schema exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.