How do you write tools for openclaw?

By tools, I mean executable scripts that can deterministically perform some functionality. In official documentation, I find two ways: Openclaw plugin, mcp server The first seems a bit off to me if I just want to have a simple functionality, like a tool to back up my openclaw to a repo. This simple script shouldn’t be considered a plugin I have little experience with mcp server, but having multiple mcp servers could jam the model context as well, and it is not scalable (l want something that could be searched and loaded dynamically for example) Lastly, it seems we can write skills. But when reading skills, they are just markdown prompts, which defeats the purpose of tool execution that could save a bunch of tokens I also see people writing their own cli, or local script to be executed by the agent Any thoughts on which of above, or any other way, suit better for openclaw?