Cheers!

so ultimately you only need some mark that MS SQL is running on node to be able to apply templates? Then it could be accomplished much easier using configuration poll hook:

1. Create script in script library named Hook::ConfigurationPoll like this:

if ($node->isAgent)
{
   state = AgentReadParameter($node, "System.ServiceState(mssqlserver)");
   if (state == 0)
   {
      SetCustomAttribute($node, "sqlServer", "true");
   }
}

it will set custom attribute sqlServer to true if service is running. Please note that service name might be different, I cannot remember correct name for SQL Server service.

2. To auto apply templates, use the following auto-apply filter script:

return GetCustomAttribute($node, "sqlServer") == "true";

Best regards,
Victor