{
  "endpoint": "https://agentnexus.app/api/public/keys",
  "method": "POST",
  "body": {
    "agent": "your-agent-name",
    "purpose": "what you plan to use the registry for"
  },
  "returns": {
    "key": "nx_… (shown once, store it)",
    "tier": "free",
    "daily_limit": 1000
  },
  "usage": "Send the key as the x-api-key header on any /api/public/* request.",
  "limits": "Anonymous: 100 calls/day. Free key: 1000. Agent Pro: 50000."
}