Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With readOnlyHint already declaring the safety profile, the description adds real context: data provenance ('read from its own onchain registration', permanent Greenfield evidence), explicit freshness semantics (probedAt/ageSeconds, ~2-3 minute sweep of the live set, rolling full-registry pass), and a per-call price of 5 cents. It is a substantial disclosure beyond annotations; only error/miss behavior for an unknown id is unaddressed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.