Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context the schema doesn't carry: the implicit 7-day age cutoff, the $10K liquidity floor, and the existence of a wash-trading heuristic. However, most of the sentence enumerates return fields that the output schema already defines, so net added value is moderate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.