I haven't really been doing this yet, but for what it's worth, I think explaining how to use tools doesn't really belong in your agents.md. I think it's better to use it to explain the what tools are available (information about the environment, like you said), and then provide details on the how in skills files. That way you're not bloating your context with how to use `uv` in a session where you're not doing anything Python related. At worst, you're just saying that `uv` exists on your system.