PROTOCOL
What Is MCP (Model Context Protocol)?
MCP (Model Context Protocol) is an open protocol that standardizes how an AI application connects to external tools, data sources, and systems. Rather than writing a custom integration for every tool a model might use, you implement one interface that any compliant client and server can speak.
What the video explains
One adapter between a model and its tools
An MCP, or Model Context Protocol, is a standard adapter that lets an AI model use tools. On its own, an LLM is just a text-in, text-out box. It can reason, but it can't act on anything by itself. In an MCP setup the model sits on the client side.
What most people call MCP actually refers to the MCP server, which is where the tools are described and linked. It helps to think of that server as a catalog: every command the model is allowed to use is named and described in it. Two examples would be "create a meeting" and "search files".
Walking through one call
Say a user, Mike, sends the model an instruction: create a meeting on the third of April with Rachel. The model knows an MCP server is available, so it first checks the catalog to see which tools it has access to.
Under each tool is a short explanation of how to use it: what to pass in, what comes back, and what the tool actually does. For "create meeting", the description says it books a calendar slot, it needs a title, a date, and a list of people, and it returns an event link. The server sends back this metadata for every tool, and from it the model works out that "create meeting" is the one it needs.
The model then writes the exact input for that tool. The server reads the request, creates the meeting, and returns the result: a link to a meeting that now exists. The meeting is on the calendar and the people are invited. That is MCP, one protocol that lets any recent model use a tool.
The problem MCP solves
Before MCP, wiring a model to N tools across M applications meant roughly N×M custom integrations. A Slack app talking to one model needs different glue code than the same app talking to another, and every new tool is its own one-off wiring job.
MCP turns that into N+M. A tool ships one MCP server. An application ships one MCP client. Any client then talks to any server with no custom code on either side, the way any browser talks to any website because both speak HTTP.
How it works
An MCP server exposes three primitives. Tools are functions the model can call, each with a name, a description, and an input schema. Resources are data the model can read, like a file or a query result. Prompts are reusable templates the server offers.
An MCP client, usually built into an AI application, connects to one or more servers, discovers what each exposes, and hands that to the model. The model never speaks MCP itself. It reads the tool descriptions, decides when to call one, and the client carries the protocol traffic.
Transport is JSON-RPC 2.0 over stdio for a local server run as a subprocess, or HTTP with Server-Sent Events for a remote one. A deliberately boring choice. MCP is not inventing a wire format, it is standardizing what goes over an existing one.
MCP vs. a plain function call
A model that supports tool calling can already invoke a function you define inline, in the same codebase, for one conversation. MCP is for when the tool should work across applications and be maintained on its own, separate from any app that uses it.
Wiring a model to your own database inside your own app? An inline tool definition is simpler, and MCP is overhead. Building a GitHub integration you want every MCP-compatible client to use? MCP is the right layer.
FAQ
- Does MCP require a specific model provider?
- No. MCP is provider-agnostic. It defines the protocol between a client and a server; which model the client is built around is a separate decision.
- Is MCP the same as a plugin system?
- Similar in spirit, but standardized rather than tied to one vendor. A plugin system built for one application only works in that application. An MCP server works with any MCP-compliant client.
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Last updated 2026-09-06