Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full transparency burden. It discloses the dual-mode operation (AI vs heuristic) and the return format (summary + JSON). It does not cover error cases or side effects, but for a decomposition tool, the behavior is well-communicated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.