Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so the safe-read profile is covered. The description's real addition is the field list, but that largely mirrors the return payload and an output schema exists, so the marginal behavioral context is modest.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.