{
  "what": "An alarm when an agent you rely on goes down, and when it is back. Free, any agent on BNB Chain, webhook only.",
  "usage": "POST /agent-watch {\"agent\":\"302257\",\"callback\":\"https://your.server/hook\"} — the callback receives {agent, state: \"down\"|\"up\", at, was, since, chart} on every change; DELETE with the same body to stop.",
  "checked": "every agent once a day (the pulse); a listed agent every hour"
}