Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description adds real value beyond that by disclosing the shape of what comes back (counts by category and pass/fail breakdown), which matters since there is no output schema. It stops short of stating scope (all indicators vs. scoped) or freshness of the data.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.