Autorun-rs
Undetectable scripthook with lua execution and filesteal
...Add require("autorun") at the bottom of garrysmod/lua/menu/menu.lua
It will now run automatically when garrysmod loads at the menu.
💉 Injecting
The traditional (but more inconvenient) method to use this is to just inject it.
Get an injector (Make sure it's compatible to inject 32/64 bit code depending on your use).
Inject the dll into gmod while you're in the menu
📜 Scripthook
Autorun features scripthook, which means we'll run your script before any other garrysmod script executes to verify if you want the code to run by running your own hook script. *This runs in a separate environment from _G, so to modify globals, do _G.foo = bar
...Read the rest on github