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, and the description adds nothing on top of that. It says nothing about whether quotas are per-region limits vs. current usage, whether missing regions error out, or what a quota response contains. For a near-empty description against annotations, this is below the added-value bar.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.