Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint/non-destructive/closed-world, so safety is covered. The description adds value beyond them: it flags the output is informational not advice, scopes passport reach as context-only, and instructs combining with a consultation — useful framing not present in structured fields. It says nothing about rate limits or caching, but that is minor given the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.