Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds only a partial list of returned metrics; it says nothing about freshness/lag of analytics, supported platforms, time-window behavior, or permissions, which are the real unknowns for an open-world analytics read.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.