What's the best way to install LLM agent skill files with Nix?

Skills are basically markdown documents providing documentation/instructions for LLMs.

As an example, I would like to have a "Nix/NixOS skill" available to opencode when I'm in my NixOS configuration directory. For example one from agentskills.io . What's the best way to install that with Nix?

There seem to be some non-Nix tools for doing this, like skills.

I did some searching online but I couldn't find a simple solution to this.