Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the description adds value by explaining the output variants (authenticated:true with empty pending[] vs. connect_url). This extra context beyond annotations is useful for understanding the tool's state-dependent responses.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.