Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is carried by structured data. The description adds nothing beyond that — it doesn't say the existing note is overwritten irreversibly, what happens if the watchId doesn't exist, or whether permissions are required. For a destructive mutation with zero added context, this is a clear gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.