Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already carry readOnly/idempotent/non-destructive, so the safety profile is covered. The description still adds non-obvious semantics beyond them: `as_of` is a sync time that can lag transactions, and a negative CLOSING_BOOKED on a credit account means amount owed rather than overdrawn. It does not cover auth, pagination, or rate limits, keeping it just below 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.