Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description itself carries the full burden. It reveals that the returned node is 'walkable' and uses a 'world point', which is useful, but it omits key behavioral details: what happens if no node is walkable, whether the point is clamped/projected, return structure, or whether the map must be loaded.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.