So is the MCP server acting like a middleman between the llm and the application you want to control? Like, could I give the MCP server the ability to say exec

So is the MCP server acting like a middleman between the llm and the application you want to control? Like, could I give the MCP server the ability to say exec Unix code on my machine and then tell the LLM "here's the MCP server, this function can execute Unix code and get back the response". Then I can tell the LLM, "create an application using the MCP server that will listen to a GitHub webhook and git pull when the webhook hits and have it running" then the LLM would generate the commands necessary to do that and run them through the MCP server which just executed the Unix code. And viola? I've gotten an llm to create files and run system commands for me. Is that the most barebones application?