Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description usefully adds that returns are 'compact' by default and that lookup is exact-match rather than fuzzy, but it says nothing about the include_detail flag that toggles the detailed form, which is the one behavioral lever an agent would want explained.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.