Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint, openWorldHint, idempotentHint, destructiveHint=false). The description adds useful non-annotation-specific behavior: cursor pagination and a credit cost of 10, which helps the agent anticipate side effects and usage cost.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.