Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It reveals only that a city name is typed into a search field, but does not disclose whether the action submits, overwrites existing text, requires a loaded page, or is idempotent. This is a thin behavioral disclosure for an action tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.