phpmnd is a tool that aims to help you to detect magic numbers in your PHP code. By default 0 and 1 are not considered to be magic numbers. A magic number is a numeric literal that is not defined as a constant, but which may change at a later stage, and therefore can be hard to update. It's considered a bad programming practice to use numbers directly in any source code without an explanation. In most cases this makes programs harder to read, understand, and maintain.