qtcontroller.xml

 <TestManagementPluginSection>
    <Plugins>
      <Plugin classname="Enlighten.TFS.TestManagement.Controller.AgentFilter.AgentFilterPlugin, Enlighten.TFS.TestManagement.Controller.AgentFilter"/>      
    </Plugins>
  </TestManagementPluginSection>

TcmRunControllerPlugin.cs

using Microsoft.TeamFoundation.TestManagement.Controller;
using Microsoft.VisualStudio.TestTools.Common;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using System.Xml.Serialization;

namespace Enlighten.TFS.TestManagement.Controller.AgentFilter
{
    public class AgentFilterPlugin : TcmRunControllerPlugin
    {
        public override void Initialize(Microsoft.TeamFoundation.TestManagement.Client.ITestRun run, Microsoft.VisualStudio.TestTools.Common.TestRunConfiguration runConfig)
        {           
            var testConfigurationIds = run.QueryResults().Select(r => r.TestConfigurationId).Distinct();
            foreach (var testConfigurationId in testConfigurationIds)
            {
                var config = run.Project.TestConfigurations.Find(testConfigurationId);
                foreach (var key in config.Values.Keys)
                {
                    if (!runConfig.AgentProperties.ContainsKey(key))
                    {
                        runConfig.AgentProperties[key] = config.Values[key];
                    }
                    else
                    {
                        runConfig.AgentProperties[key] += "," + config.Values[key];
                    }
                }
            }
        }

    }
}