Rewrote Command Line Argument Handling

A developer replaced the Rust `clap` crate with LLM-generated argument-parsing code written by Gemini 3.8 Flash via OpenRouter, cutting the compiled executable size by 300 kB and argument parsing time from 20 microseconds to about 1 microsecond. The developer wrote a 120-line Markdown spec and paid roughly $0.02 per generation, needing two attempts after the first omitted an argument. The replacement handles the important command line arguments but does not cover edge cases as well as `clap`.

My Rust program used the clap crate to handle command line arguments, and it worked well. But I wanted to try using an LLM to generate some custom code to replace it, to see if there would be any performance improvements or reductions in bloat. I wrote a 120-line spec , complete with examples, in Markdown , and set Gemini 3.8 Flash on OpenRouter to implementing the code. The first time, I forgot an argument, so I had to generate it twice. Each generation cost me about $0.02, so it was affordable. Some observations : • Removing clap from my program reduced the compiled executable file size by 300 kB, and reduced the time required in argument parsing from 20 microseconds to about 1 microsecond. • My vibe-coded replacement function does not handle edge cases as well, but it handles all the important command line arguments I needed.