Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description goes beyond them by disclosing the cost model (free, no payment) and the special 'IC' grade for allowlisted issuer-controlled assets, which is the kind of nuance an agent would otherwise misread as a data error. It still omits rate limiting or whether the grade is cached.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.