Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the notion of a 'stable' public-link URL, which is a useful behavioral detail, but does not disclose any additional traits like rate limits, authentication, or return format variations. With annotations covering the safety aspects, a score of 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.