{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://git.eeqj.de/sneak/chat/schema/s2s/link.json",
  "title": "S2S Link",
  "description": "Server link establishment request/response.",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "format": "uuid"
    },
    "type": {
      "const": "link"
    },
    "ts": {
      "type": "string",
      "format": "date-time"
    },
    "origin": {
      "type": "string",
      "description": "Requesting server name."
    },
    "version": {
      "type": "string",
      "description": "Protocol version of the requesting server."
    },
    "auth": {
      "type": "string",
      "description": "HMAC signature over the link request using the shared federation key."
    },
    "capabilities": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "List of supported protocol capabilities.",
      "examples": [["relay", "sync", "presence"]]
    }
  },
  "required": ["id", "type", "ts", "origin", "auth"]
}