Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds almost nothing beyond that — it does not explain what tabs actually get opened, whether the active file is derived from context, or what side effects (focus stealing, view changes) occur.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.