What Is MCP and Why It Matters
The Model Context Protocol explained: hosts, clients, servers, tools, resources, and prompts — and why it became the standard.
Say you've built a great tool that lets an agent search your company's internal wiki. You wire it into Claude Code. Then a teammate wants it in Cursor, another uses ChatGPT, and your support team's custom agent needs it too. Without a standard, that's four separate integrations, each written against a different tool format, each breaking on its own schedule.
The Model Context Protocol (MCP) exists to end that. It's an open standard that lets you build a tool integration once and use it from any agent that speaks the protocol, much as a USB-C port lets one cable work with many devices. In this lesson you'll learn how MCP is structured (hosts, clients, and servers), how its pieces talk to each other, what servers can offer (tools, resources, and prompts), and why it became the default way to connect agents to the rest of your world, along with its real limitations.
The problem MCP solves
Before MCP, every AI application invented its own way to plug in external capabilities. If there were 10 AI apps and 100 services worth connecting (GitHub, Slack, Postgres, Google Drive, your internal APIs), you potentially needed 1,000 custom integrations. Each app maintained its own connectors, and each service had to pick which apps to support.
MCP turns that multiplication into addition. Each service implements one MCP server. Each AI application implements MCP support once. Now any app can use any server: 10 plus 100 implementations instead of 10 times 100.
| Without MCP | With MCP |
|---|---|
| Every app writes its own GitHub integration | GitHub (or the community) ships one MCP server |
| Tool definitions differ per app | One protocol for discovering and calling tools |
| Switching agents means rebuilding integrations | Point your new agent at the same servers |
| Your internal tools work in only one place | Your internal MCP server works in any MCP-capable agent |
Anthropic introduced MCP as an open specification in late 2024. Over the following year it was adopted across the industry, including by OpenAI, Google, and Microsoft, and it's supported by Claude Code, Claude's desktop and web apps, ChatGPT, OpenAI Codex, Gemini CLI, Cursor, VS Code with GitHub Copilot, and many more. In December 2025, Anthropic donated MCP to the Agentic AI Foundation, a new fund under the Linux Foundation co-founded with OpenAI and Block, so no single company controls it. Today it's the closest thing the agent world has to a universal plug.