Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses the hosted-signing model and that the key is not persisted, which is security-relevant context, but it says nothing about the effect of acceptance (irreversibility, what state changes, whether an on-chain transaction results) or any prerequisites. Adequate disclosure of credential handling, incomplete on mutation semantics.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.