Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose the semantic contents of the result (actionable items awaiting you). However, it says nothing about whether the operation is read-only, ordering, permission requirements, or whether acting on items changes state. Useful content disclosure but incomplete behavioral context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.