Many thanks for this.

I need to look more deeply but gtools seems to use system calls. My fallback is to run scripts using system calls, but ideally there would be persistence so the perl side of things can run more analyses without having to restart scripts and reload data.

It also requires the user have a working perl. My system has a large dependency tree that includes many XS libs so can't be fatpacked. Compiling using RTools and installing using a project level local::lib is not impossible but does get complex and hard to control across user environments. ...Although now I read more I see it can compile such libs.

Thanks also for the sockets/pipes advice. I knew about arbitrary code but had never considered external websites hitting local services.