Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool as read-only, idempotent, and non-destructive, and the description adds valuable context: it is a research signal, not investment advice, costs $0.05 per call, and returns a payment-required error when unpaid. It also discloses the renormalization of composite_score and the inclusion of governance flags, going beyond what annotations convey.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.