Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds the useful output contract of one entry per input wallet with order preserved, but says nothing about partial failures, invalid addresses, or what "black-box" scoring means in practice. A 3 is appropriate given the lower bar set by rich annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.