Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and discloses the key behaviors: points become waypoints, lines/polygons become tracks, and output is GPX 1.1 XML as plain text. It does not state edge-case behavior (e.g., CRS handling, attribute preservation, unsupported geometry types), but the core conversion profile is transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.