How to execute a cgi to format WordPress Post ?

Hi Guys,

I’d like to reformat WordPress Posts by passing it to a cgi of mine. I know how to get the result back (see here https://reboltutorial.com/blog/how-to-include-rebol-cgi-within-php/) but I’m new to codex and I don’t know where to do so especially if I guess other plugins are interfering in the process chain.