Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld, non-destructive, so the safety profile is covered; the description adds real value on top by disclosing auth posture (free, keyless, never asks for a wallet signature), pointing to a signing-spec endpoint for the write path, and explaining that stake is snapshotted at post time. The only blemish is redundancy: "free and keyless, nothing to sign" is restated at the end.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.