Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the mutation profile (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false), lowering the bar. The description adds one useful behavioral fact beyond them: the call returns an Ed25519-signed receipt. It does not cover duplicate handling, moderation, or rate limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.