Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds substantive behavior beyond the annotations: it records a request but does not guarantee a human has joined or replied, it errors when no AI assistant is assigned, and it constrains follow-up messaging. None of this is derivable from readOnlyHint=false / destructiveHint=false / idempotentHint=false.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.