Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint, so the safety profile is covered. The description adds the useful content scope (step order, view, action, route transitions), but says nothing about error behavior, version-mismatch handling, or size/limits of the manifest.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.