Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It discloses foregrounding behavior but omits whether the action requires permissions, what happens if the tab is already active or invalid, whether it changes focus across windows, and what the operation returns. This is a significant gap for a mutation/UI-control tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.