Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully clarifies the meaning of priceUsdPerCall (flat per-call fee, includes maxTokensCap for chat/embedding), which is real value, but it says nothing about whether this is read-only, what permissions are needed, or what the response contains beyond that one field.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.