Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, but it only states 'List all columns' with no additional behavioral context. It does not disclose whether it returns paginated results, whether it is read-only, any access requirements, or what happens if the table is empty. The verb 'list' suggests a read operation but no explicit reassurance is given.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.