{
  "context": "This evaluation assesses how well the engineer uses webrtc-adapter's DTMF support capabilities to send touch-tone signals over WebRTC audio connections. The focus is on proper usage of the RTCRtpSender.dtmf property, RTCDTMFSender interface, and understanding audio-only DTMF sender creation.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "Import webrtc-adapter",
      "description": "Code imports the webrtc-adapter package to enable cross-browser DTMF support",
      "max_score": 10
    },
    {
      "name": "RTCPeerConnection creation",
      "description": "Creates an RTCPeerConnection instance for establishing the WebRTC connection",
      "max_score": 10
    },
    {
      "name": "Audio track addition",
      "description": "Adds an audio track to the peer connection using addTrack() method, which is required for DTMF functionality",
      "max_score": 15
    },
    {
      "name": "Access RTCRtpSender.dtmf",
      "description": "Accesses the dtmf property on the RTCRtpSender to obtain the RTCDTMFSender instance",
      "max_score": 20
    },
    {
      "name": "Check DTMF availability",
      "description": "Checks if the dtmf property is null or not null to determine DTMF sender availability (null for non-audio tracks, non-null for audio tracks)",
      "max_score": 15
    },
    {
      "name": "Use insertDTMF method",
      "description": "Calls the insertDTMF() method on the RTCDTMFSender to send DTMF tones",
      "max_score": 20
    },
    {
      "name": "Configure timing parameters",
      "description": "Passes duration and interToneGap parameters to insertDTMF() to control tone timing (e.g., insertDTMF(tones, duration, interToneGap))",
      "max_score": 10
    }
  ]
}