Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description must carry full responsibility for disclosing behavior. It only says 'List active database sessions' without mentioning whether this is a read-only operation, whether it requires an existing connection, how 'active' is defined, or any potential side effects. This is minimal and lacks transparency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.