Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does well: it discloses newest-first ordering, the limit range (1-20) and default (20), the filtering behavior ('Removed and encrypted-community posts never appear'), and a special error case ('unknown or vetoed answers not_found'). This is unusually rich for a read-only list tool, though it stops short of describing the return shape.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.