I think this where the real question is for me. When I read about MCP, the topmost question in my mind is "Why isn't this just tool calling?" I had difficulty finding an answer to this. Below, you have someone else asking "Why not just use GraphQL?" And so on.

It would probably be helpful for many of your readers if you had a focused document that addressed specifically that motivating question, together with illustrated examples. What does MCP provide, and what does it intend to solve, that a tool calling interface or RPC protocol can't?