Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, making the repeated 'Read-only' and 'No files modified' statements redundant. The description still adds useful behavioral context by specifying that the original token is excluded and that an empty list is returned when no siblings exist.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.