Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the behavioral disclosure burden. It reveals that the operation is scoped to the authenticated user, that it only lists existing characters, and that character creation is not possible through the API. While it doesn't describe output shape or pagination, the read-only nature is clear from the verb and context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.