Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the behavioral burden, and it usefully explains the sign convention for positionPctChange, which helps interpret results. However, it omits ordering, freshness window, pagination behavior beyond the schema's limit, and any confirmation that this is a read-only feed operation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.