Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive), but the description adds what those annotations cannot: the author-only authorization requirement and the fact that the full payload (sections, citations, structured, markdown) is returned so it can be diffed against HEAD. It stops short of noting any failure modes, such as a not-found or not-authorized response, which keeps it from a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.