Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must convey behavior. 'List' implies a read-only operation, but it does not disclose details such as pagination, access filters, or whether the returned environments are limited to the current user's permissions. The description is minimally transparent but does not add context beyond the verb itself.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.