Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the bar is low. The description adds one useful behavioral fact: results are scoped to the current site and limited to adopted devices. It says nothing about pagination behavior or result volume, which matters given limit/offset parameters.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.