{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://git.eeqj.de/sneak/chat/schema/commands/PING.json",
  "title": "PING",
  "description": "Keepalive. C2S or S2S. Server responds with PONG. RFC 1459 §4.6.2.",
  "$ref": "../message.json",
  "properties": {
    "command": { "const": "PING" },
    "body": {
      "type": "array",
      "items": { "type": "string" },
      "description": "Opaque token to be echoed in PONG (single-element array).",
      "maxItems": 1
    }
  },
  "required": ["command"],
  "examples": [
    { "command": "PING", "body": ["1707580000"] }
  ]
}