MCPTool.METAR.pas

(*
  MCP Tool: METAR
  
  This unit implements a tool that retrieves METAR weather information for a given station.

  Sample response:

  {
    "content": [
      {
        "type": "text",
        "text": "PARIS-CHARLES DE GAULLE\nLFPG 231130Z 24010KT 210V270 9999 FEW030 18/11 Q1022 NOSIG"
      }
    ],
    "isError": false
  }
*)

unit MCPTool.METAR;

uses
   System.Net, System.Encoding,
   Networking.MCP;

type
   TMETARTool = class (TMCPTool)
      class function Description : String; override;
      begin
         Result := 'Get a METAR from a station ID';
      end;
      class function InputSchema : JSONVariant; override;
      begin
         Result := JSON.Serialize(
            record
               'type' := 'object';
               properties := record
                  station_id := record
                     'type' := 'string';
                     "description" := "ICAO code for the weather station (e.g., LFPG, KJFK)";
                  end;
               end;
               required := [ "station_id" ];
            end
         );
      end;
      class function Call(params : JSONVariant) : JSONVariant; override;
      begin
         var dataMetar, dataStation : String;
         var stationParam := URLEncodedEncoder.Encode(params.station_id);
         var status := HttpQuery.GetData('https://aviationweather.gov/api/data/metar?ids=' + stationParam, dataMetar);
         case status of
            200 : begin
               // prefix with station name to allow the model to correct hallucinations
               HttpQuery.GetData('https://aviationweather.gov/api/data/stationinfo?ids=' + stationParam, dataStation);
               dataMetar := JSON.Parse(dataStation)[0].site + #10 + dataMetar;
            end;
            204 : begin
               // used for no data by the API, which in our case means invalid station  id
               dataMetar := 'Invalid station ' + stationParam;
            end;
         else
            dataMetar := 'Request failed with status ' + status.ToString;
         end;
         Result := JSON.Serialize(record
            content := [
               record
                  'type' := 'text';
                  text := dataMetar;
               end
            ];
            isError := False;
         end);
      end;
   end;