Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish read-only, idempotent, closed-world behavior. Beyond that, the description discloses the actual content the agent will receive (free items, workflow steps, options, materials, customer requirements), which is the meaningful behavioral signal for an informational tool. It does not say whether the content is static or time-sensitive, which keeps it from 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.