Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover mutation/safety (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the bar is lower. The description adds the launch-vs-activate nuance, implying an already-running app is brought forward rather than relaunched. It says nothing about behavior for unsupported apps, whether it steals focus, or any error/consent behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.