Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnlyHint/destructiveHint annotations, the description discloses operational and behavioral details an agent needs: cost per call, network and transport (x402 on Base), optional x-credit-token header for unlimited calls, free daily allowance, and the fact that no wallet or API key is required. It also reveals the output shape: a 0-100 reputation score with signals.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.