Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide basic hints (non-read-only, non-destructive, non-idempotent, open-world), but the description adds minimal behavioral context by specifying it's a POST request, implying it may send data or trigger an action. However, it doesn't disclose what the tool actually does (e.g., sends a test ping, validates connectivity, returns a status), rate limits, authentication needs, or expected outcomes. With annotations present, the bar is lower, but the description adds only limited value beyond them.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.