Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, openWorldHint, and idempotentHint. The description adds context about the external API dependency (GSI) and the output granularity (municipality code and town name). It does not disclose rate limits or error behaviors, but with annotations covering safety, this is acceptable.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.