Does the description explain when to use this tool, when not to, or what alternatives exist?
It names the exact preferred workflow: list webhooks, then use delete_webhook_by_id, and gives the condition that makes this tool the fallback (clients that omit DELETE request bodies). That is explicit when-to-use, when-to-prefer-an-alternative guidance, which is the top of this scale.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.