Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, openWorld, non-idempotent, non-destructive, so the safety profile is covered. The description adds genuinely new context beyond that: the pricing model ($0.01 per successful call, failed calls free) and the fact it uses a real browser, both operationally relevant. It doesn't mention rate limits or latency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.