Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already state readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. Beyond that, the description discloses what the response will report: the direction of the recommendation, the savings amount, and the cliff-point warning. It still does not state assumptions such as how default deductions of 0 affect the result, but it adds real behavioral value on top of the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.