Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden and does not say whether this is a read-only, side-effect-free call, how often status can be polled, or whether presence is cached/stale. For a presence lookup with related tools like 'watch' and 'poll', this context matters.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.