Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description does add one genuinely non-obvious fact beyond them: items already read remain readable after cancellation, implying partial results survive. It says nothing about in-flight items, error/partial-failure behavior, or permissions, so a 3 is warranted.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.