Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The parenthetical '(Read-only: liest nur das Dateiverzeichnis, keine Änderungen.)' largely restates that, adding only the detail that it reads a file directory. The useful extra is the enumeration of returned fields, not the behavior disclosure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.