What Is an MCP Server? A Plain-English Guide

Here is the problem MCP was invented to solve. An AI model on its own is a brain in a jar: it can reason and write, but it cannot see your calendar, read your database, search your files, or take an action in another app. To make it useful, you have to connect it to those things — and historically every connection was a bespoke piece of plumbing. Connect a model to your database one way, your file store another way, your ticketing system a third way. The combinations multiplied, nothing was reusable, and every new tool meant new custom code.

The Model Context Protocol (MCP) is the fix. It is an open standard, introduced by Anthropic in November 2024, that defines one common way for AI models to connect to external tools and data. The usual analogy is the right one: MCP is a universal port for AI — the USB-C of agentic software. Instead of dozens of one-off integrations, you expose a tool once in the MCP format, and any MCP-aware AI can use it.

So what exactly is an MCP "server"?

In MCP there are two roles. The client is the AI side — the app or model that wants to do something (Claude, ChatGPT, an agent in your IDE). The server is the connector that exposes a specific capability to that client. An MCP server might wrap your company database, a GitHub repository, a Google Drive, a payments system, or a weather API. It advertises three kinds of things the model can use:

Tools — actions the model can take (create an invoice, run a query, send a message).

Resources — data the model can read (documents, records, files).

Prompts — prepackaged instructions the server offers for common tasks.

The model connects to the server, asks "what can you do?", and the server answers with its list. From there the model can call those tools and read those resources through the same standard interface every time. That standardization is the entire point — and it is why MCP servers are reusable across completely different AI products.

Why MCP won — fast

Open standards usually take years to gain traction. MCP took months. Within roughly half a year of launch, every major provider had adopted it: OpenAI added MCP support across its Agents SDK, Responses API, and ChatGPT desktop in March 2025; Google DeepMind confirmed support in Gemini in April 2025; Microsoft brought it to Copilot; and developer tools like Cursor, Replit, and VS Code built it in. The growth numbers are striking — by March 2026 the protocol crossed roughly 97 million monthly SDK downloads, up from about 2 million at its November 2024 launch.

Then came the move that sealed it as neutral infrastructure: in December 2025 Anthropic donated MCP to the Agentic AI Foundation under the Linux Foundation — co-founded with Block and OpenAI, and backed by Google, Microsoft, AWS, Cloudflare, and Bloomberg. A protocol governed by a neutral foundation, supported by competitors who rarely agree on anything, is a protocol you can build on without betting on one vendor. By mid-2026 the official MCP registry indexed on the order of 9,600+ distinct servers — a real ecosystem, not a demo.

What this means for you

You do not need to write code to benefit from MCP. The practical implications are simpler:

Your AI assistant can now do real work, not just talk. With the right MCP servers connected, a model can pull a live report, update a record, or draft a reply grounded in your actual data — instead of guessing.

Skills carry across tools. Because the standard is shared, a capability exposed as an MCP server works the same whether you are in Claude, ChatGPT, or your editor. You are no longer locked to one assistant.

Picking servers is the new skill. The value is increasingly in which servers you connect and how you combine them. A good MCP server is reputable, scoped to a clear job, and safe to grant access to — which is exactly why curation matters.

MCP is one of the five building blocks we mapped in our AI Asset Stack guide: the connection layer that gives a model something real to reach. If skills are packaged know-how, MCP servers are the wiring to the outside world — and in 2026 that wiring is, finally, standard.

If you want to start, browse the MCP servers in our catalogue: each is vetted, categorized, and described in plain language — and filtered to leave out the gambling and high-risk-speculation servers that do not belong in a serious toolkit.