public string DisabledTooltip {get; set;}

{
  //Set the tool's loadOnClick attribute to "false" in the config.daml. 
  //This will allow the tool to be created when Pro launches, so that the disabledText property can display customized text at startup.
  //Remove the "condition" attribute from the tool. Use the OnUpdate method(below) to set the enable\disable state of the tool.
  //Add the OnUpdate method to the tool.
  //Note: since OnUpdate is called very frequently, you should avoid lengthy operations in this method 
  //as this would reduce the responsiveness of the application user interface.
  {
    bool enableState = true; //TODO: Code your enabled state  
    bool criteria = true;  //TODO: Evaluate criteria for disabledText  

    if (enableState)
    {
      Enabled = true;  //tool is enabled  
    }
    else
    {
      Enabled = false;  //tool is disabled  
                        //customize your disabledText here  
      if (criteria)
        DisabledTooltip = "Missing criteria 1";
    }
  }
}