Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the '[SIDE EFFECTS]: None (pure read-only query)' line largely restates structured data. It adds useful scoping context (this is a discovery-stage sizing query, not a mutation), but says nothing about latency, caching, or result shape beyond what the output schema covers. With annotations carrying the safety profile, 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.