code: func (p *Proxy) shouldInjectVars(args []string) bool {
  	if len(args) == 0 {
  		return false
  	}
  
  	return args[0] == "plan" || args[0] == "apply" || args[0] == "destroy" || args[0] == "refresh"
  }
docs: // shouldInjectVars checks if the command accepts -var flags.