Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, fully disclosing safety and behavior. The description adds no extra behavioral context (e.g., no mention of rate limits, authentication, or side effects). With annotations doing the work, 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.