Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It does disclose the no-path case ('message if no path found') and the depth default, which helps, but it never states that the operation is read-only, whether edge direction means dependencies-of-source or dependents, how cycles are handled, or the cost of raising max_depth on a large graph.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.