Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate readOnly=false, idempotent=false, destructive=false, so the description only needs to add extra behavioral context. It does add scope/auth guidance by saying 'signed-in user' and 'REST-only', but it does not disclose side effects such as whether existing planned workouts are overwritten, how cadence is applied, or whether the operation can fail due to conflicts.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.