Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses key behaviors: rounding up support, default tip and split, currency-agnostic nature, and the computed outputs (tip, total, per-person share, effective percentage). This gives the agent a complete picture of what the tool does and its side-effect-free calculation nature.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.