Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It does not disclose that planning is a read-only operation (no side effects), nor does it mention potential waits for plan generation, required permissions, or output format. Agent lacks awareness of its non-destructive nature.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.