Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the description need not restate read-only safety. It does add an authentication requirement, which is useful context, but it omits important behavioral traits of a subscription tool: whether it streams repeatedly, waits for a single message, requires an active WebSocket connection, or how timeoutMs/messageCount control execution.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.