Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It lists the summary contents but doesn't disclose whether the tool is read-only, if it requires specific permissions, how fresh the data is, or any side effects. It provides minimal behavioral insight beyond its purpose.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.