What MCP Actually Is (And Why It Exists)

What is MCP? MCPs are a way to give AI applications the external context/capabilities they need to complete their mission. Kind of a blanket statement, I know. You're probably wondering: doesn’t RAG already do this? What about tools? And you'd be right to think that, somewhat. These are all ways to give AI context. With RAG, you typically embed and store context somewhere if you're not trying to overshoot your context window by just sending an entire PDF to the LLM. This context is then retrieved each time the user makes a query to your app. Although, realistically, you should have some form of reasoning that decides whether the user's query actually needs additional context because they could literally just be asking your app: "How are you?" 😭 Anyways, Back to MCPs. MCPs are more closely related to tools (function calling), but they also support resources, which makes them relevant to RAG-like systems too. And I’m going to explain why MCP exists with a short example: The Problem MCP