What MCP is and why it exists

Model Context Protocol (MCP) · Essentials · 8 min

Knowing the problem MCP solves tells you when to reach for it instead of writing one-off tool code.

You already know that a model can ask your code to run a function (tool calling). The catch is that every AI app wires those functions up in its own way. A GitHub integration written for one chat app has to be rewritten for an IDE, and again for your own agent.

Think of phone chargers before USB-C: every brand had its own plug. The Model Context Protocol (MCP) is the USB-C for AI apps. A protocol is just an agreed set of messages two programs exchange. MCP fixes those messages, so:

  • a team writes an MCP server for their system (GitHub, a database, your company wiki) once,
  • any app that speaks MCP (Claude, Claude Code, Cursor, VS Code, your own agent) can plug it in.

Without a standard, N apps and M systems need N times M integrations. With MCP they need N plus M.

MCP is open source. Anthropic published it in late 2024 and it is now governed in the open, with official SDKs (software development kits: libraries that implement the protocol for you) in Python, TypeScript, Go, C#, Java, Rust and more.

What MCP is not: it is not a model, not an agent framework, and it does not decide what the model does. It only standardizes how an app discovers what a server offers and calls it. The app and its model still decide when to use it.

The current specification (the official rulebook) is dated 2026-07-28. MCP names versions by the date of their last breaking change.

Remember

  • MCP standardizes how AI apps talk to tools and data sources
  • Write a server once, use it from any MCP-capable app
  • It turns N x M custom integrations into N + M
  • Versions are dates; the current spec is 2026-07-28

Watch out for

  • Thinking MCP replaces tool calling. It builds on it: MCP is how the tools get to the app in a standard way.

Check yourself

  1. A company has 3 AI apps and 4 internal systems. Roughly how many integrations do they need with MCP?
  2. Which statement about MCP is true?

Sign in to answer, see the explanations, and get this lesson back as a quick review later.

Official docs: modelcontextprotocol.io/docs/2026-07-28/getting-started/intro