Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnly, idempotent, non-destructive, closed-world. The description adds genuinely new behavioral context: modelled figures are labelled as such in record names, the scope is China-only, and modelled values are not official statistics. That provenance caveat is the most valuable disclosure here and is not derivable from the structured fields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.