Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description should disclose behavioral traits like pagination, default scope, or output format. It only says 'List firewall aliases', omitting details about whether it lists all aliases or supports filtering (the search param is only in the schema). This leaves the agent uncertain about the tool's exact behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.