/commands are like macros or mayyybe aliases. You just put in the commands you see yourself repeating often, like "commit the unstaged files in distinct commits, use xxx style for the commit messages..." - then you can iterate on it if you see any gaps or confusion, even give example commands to use in the different steps.

Skills on the other hand are commands ON STEROIDS. They can be packaged with actual scripts and executables, the PEP723 Python style + uv is super useful.

I have one skill for example that uses Python+Treesitter to check the unit thest quality of a Go project. It does some AST magic to check the code for repetition, stupid things like sleeps and relative timestamps etc. A /command _can_ do it, but it's not as efficient, the scripts for the skill are specifically designed for LLM use and output the result in a hyper-compact form a human could never be arsed to read.