Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden, and it does disclose the return shape including the manager_id = None case, plus that name matching can be partial. It omits what happens on ambiguous partial matches (multiple hits?), what happens when nothing matches, and any auth/scope requirements, which matters for a lookup with fuzzy matching.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.