Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=false and idempotentHint=true, and the description explains why a 'query' can mutate: it 'may create or update a tracked research demand for missing or incomplete knowledge.' That side-effect disclosure is real value beyond the structured hints, though it doesn't cover latency, auth, or response shape.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.