Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true); the description adds the key behavioral fact that the note is not sent to the customer and is visible to authorized teammates. It does not discuss idempotency or whether an existing note is appended versus replaced, which keeps it short of a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.