query BuildRunAgents($buildId: ID!) {
  buildRunAgents(buildId: $buildId) {
    agent {
      id
      name
      hostname
      version
      osVersion
      architecture
    }
    isBuildAgent
    available
    unavailableReason
  }
}

{
  "buildId": "id"
}

{
  "data": {
    "buildRunAgents": [
      {
        "agent": {
          "id": "id",
          "name": "string",
          "hostname": "string",
          "version": "string",
          "osVersion": "string",
          "architecture": "string"
        },
        "isBuildAgent": true,
        "available": true,
        "unavailableReason": "OFFLINE"
      }
    ]
  }
}