Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description goes beyond annotations by explaining that MeritValue holds no market-data licence and never returns a live quote, so the caller must provide the price. It also warns against presenting a guessed price as real, adding meaningful behavioral context that is not in the readOnlyHint or openWorldHint flags.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.