Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, non-destructive, open-world semantics, so the description's real contribution is the BYOK disclosure — credentials transit in-memory only and are never stored — which an agent cannot infer from any structured field. It stops short of mentioning pagination/result caps or JQL error behavior, so 4 not 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.