I think my preferred version of this would be a hybrid. Keep the regular installer, add a file filled with information that an LLM can use to assist a human if the install script fails for some reason.
If the installer was going to succeed in a particular environment anyway, you definitely want to use that instead of an LLM that might sporadically fail for no good reason in that same environment.
If the installer fails then you have a "knowledge base" to help debug it, usable by humans or LLMs, and if it fails, well, the regular installer failed too, so hopefully you're not worse off. If the user runs the helper LLM in yolo mode then the consequences are on them.
The other problem is that without an LLM around, your install.md is suddenly not executable, which means you're effectively importing a massive dependency. Why should I have to burn some of my token quota or pay for extra tokens just to install something?
If the installer was going to succeed in a particular environment anyway, you definitely want to use that instead of an LLM that might sporadically fail for no good reason in that same environment.
If the installer fails then you have a "knowledge base" to help debug it, usable by humans or LLMs, and if it fails, well, the regular installer failed too, so hopefully you're not worse off. If the user runs the helper LLM in yolo mode then the consequences are on them.