Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds real behavioral context: the E1B special first-4-months rate, the failure mode for unauthorized combinations (authorized=false with null pay), and an output-presentation requirement (always surface calculator_url as a clickable markdown link). These are non-obvious traits that annotations and schema do not convey.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.