Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: the enumerated signer states (waiting, to sign, opened, signed, declined), the condition under which the signed PDF and download link appear, and that the call is free — useful for deciding whether to poll it.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.