Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full load and does disclose two non-obvious traits: the exact return contents and a per-call price of $0.002 USDC, which matters for agent budgeting. It omits data freshness/staleness, failure behavior for unknown mints, and whether the call is idempotent, but the cost disclosure is genuine added value.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.