Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is established. The description adds valuable behavioral context by listing the specific data points returned (connected account, auto-send toggle, daily cap, sent today, remaining budget, queued count, drain estimate), giving the agent a clear picture of what to expect without side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.