Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals a significant restriction (requires a higher plan), which is useful, but it completely hides the tool's core behavior, side effects, or return value. This partial transparency is insufficient for a tool that cannot even be invoked without an upgrade.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.