Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true), but the description contributes nothing beyond them – it does not say what fields can be changed, whether omitted fields are preserved (the point of a partial update), or what permissions are required.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.