Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations and no output schema, the description carries the full burden of explaining behavior, but it only says 'Get document styles.' It implies a read-only operation but does not disclose what is returned, whether defaults are included, side effects, or error behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.