Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the description is not required to establish safety, but it adds essentially no behavior beyond that. It does not say what a "build option" entry looks like, whether output includes compiler flags, configure arguments, or install prefixes, nor whether the underlying file must exist. For a diagnostic tool, that is a meaningful gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.