Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full behavioral burden. It usefully discloses a write side effect ('or create') for what reads like a getter, which is genuinely informative, but leaves unresolved what 'today' means (timezone/date), where the note lives, and whether a template is applied.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.