Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the description's 'read-only' restatement earns little. However, 'never accesses workspace or customer data' is a genuine data-boundary disclosure beyond the structured annotations and is valuable for an agent deciding whether the call is safe. It stops short of describing output size or rate behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.