Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, reducing the burden. The description adds valuable context about the return values (authenticated, pending, connect_url) and explains conditional behavior based on credential presence, which goes beyond the annotation metadata and helps the agent predict outcomes.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.