Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. 'Lists' implies a read operation, but nothing is disclosed about default result limits, whether campaignId scopes the results or is optional, whether the status filter defaults to a specific value, or whether all accounts' ad groups are returned. The min/max on limit hints at a 10,000-cap, but the description itself is silent on behavior that an agent would need to know to call this correctly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.