Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=true and openWorldHint=true, covering the safety profile. The description usefully adds that location values are returned inline as locationCode on sibling results, but says nothing else about behavior beyond that; with annotations carrying the safety burden, a 3 is appropriate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.