What Is an MCP Server? Model Context Protocol Explained for Businesses (2026)

Customers are starting to ask an assistant to do things for them: book the table, reorder the usual, check the invoice. For an assistant to do that with your business, it needs a safe way to call your systems. That is what an MCP server is for. This guide explains the Model Context Protocol in business terms: what it is, how it differs from an API, where it works today and what you should, and should not, expose.

What is MCP?

The Model Context Protocol is an open standard for connecting AI applications to the systems where data and actions live. It was created at Anthropic and open-sourced in November 2024. In December 2025 Anthropic donated it to the Agentic AI Foundation, "a directed fund under the Linux Foundation, co-founded by Anthropic, Block and OpenAI", so it is no longer one company's protocol. The current specification is dated 2026-07-28.

The common analogy is USB-C: before it, every device needed its own cable; before MCP, every assistant needed its own custom integration with every product. With MCP you build one server, and any assistant that speaks MCP can use it.

What does an MCP server do?

An MCP server is a small service that tells an assistant three things: which tools (actions) it offers, which resources (data) it can read, and which prompts (ready-made instructions) are available. When the assistant decides to use a tool, it sends a request; your server checks who is asking, runs the action through your existing systems and returns the result.

Here is what a single tool looks like to an assistant. This is the whole "contract": a name, a description the model reads to decide when to use it, and the inputs it must provide.

{
  "name": "reschedule_appointment",
  "description": "Move the signed-in patient's existing appointment to another free slot. Ask the patient to confirm the new time before calling.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "appointment_id": { "type": "string" },
      "new_start": { "type": "string", "format": "date-time" }
    },
    "required": ["appointment_id", "new_start"]
  }
}

Notice the description: it is written for the model, and it carries a business rule ("ask the patient to confirm"). Good tool design is mostly this kind of writing. Bad descriptions are the most common reason an assistant calls the wrong tool or calls the right one at the wrong time.

MCP vs API: what is the difference?

Your API is built for developers who read documentation and write code against it. An MCP server is built for a model that discovers your tools at runtime and decides on its own when to call them. In almost every project the MCP server calls your existing API underneath.

Where does an MCP server work in 2026?

Support has moved fast, so here is the state as of October 2026. Check each platform's documentation before you plan a launch, because several of these are previews.

The practical consequence: one well-built server reaches all of them. Adding an assistant is mostly registration, review and testing, not a rebuild. That is the idea behind our agentic AI development service.

What should a business expose?

Every action you expose is something an assistant can do in your customer's name. Start with actions that are frequent, valuable and easy to reverse; leave risky ones for later or behind a confirmation.

A good place to look for the first actions: the questions your support team answers most, and the tasks customers already try to do on your website and give up on.

How sign-in works: OAuth 2.1

A remote MCP server uses OAuth 2.1, the same family of standards behind "Sign in with Google". The customer is sent to your login page once, approves what the assistant may do, and the assistant receives a token limited to those permissions. You can revoke it at any time. The assistant never sees the password.

The 2026-07-28 specification tightened this further. The MCP blog lists "authorization hardening changes including RFC 9207 issuer validation and a formal shift away from Dynamic Client Registration (DCR) toward client metadata documents (CIMD)", and the protocol core became stateless, which removed protocol sessions. For a business owner the meaning is simple: your login stays yours, and each assistant gets narrowly scoped, revocable access.

Security risks and how to handle them

An MCP server is a new door into your systems, so treat it like one. The main risks:

• Prompt injection. The assistant reads text (an email, a review, a product page) that contains instructions, and follows them. Never let content the assistant reads widen what it may do.
• Tool poisoning. Malicious instructions hidden in a tool's description, "invisible to users but fully visible to AI models". First documented by Invariant Labs in April 2025 and now listed by OWASP. Only connect servers you control or trust, and review descriptions like code.
• Over-broad scopes. A token that can do everything will eventually do the wrong thing. One scope per group of actions; read and write separated.
• Data leakage. Every response goes into a model's context. Return only the fields the task needs.

Build, buy or use your platform's server?

You may not need to build from scratch. Shopify, for example, offers its own MCP servers for catalogue, cart, checkout and orders. Many SaaS tools ship official servers. You build your own when the actions live in your systems (a booking engine, an ERP such as Odoo, a custom CMS) or when you need rules the off-the-shelf server does not support.

• Use the platform's server when your platform has one and its tools match what customers ask for.
• Wrap your API in a custom server when your actions are specific to your business. This is the most common case.
• Combine both when, say, products come from Shopify but bookings or B2B pricing come from your own system.

Cost depends on the number of tools, the systems behind them and the review process of each assistant. A focused first server with three to five tools is a contained project; the larger cost is usually cleaning up the data and permissions underneath. Our guide on how to build an AI agent shows how we estimate both build and running costs.

Frequently asked questions

• What is an MCP server in simple terms?+−

  It is a small service that lets AI assistants use your product's actions, such as checking an order or booking an appointment, under the customer's own account and only within the permissions you allow.

• Is MCP the same as an API? Does it replace APIs?+−

  No. An API is built for developers; MCP is built for AI models that discover and call tools at runtime. An MCP server usually sits in front of your existing API and translates a few business tasks into calls to it.

• Who created MCP and is it open source?+−

  Anthropic created MCP and open-sourced it in November 2024. In December 2025 it was donated to the Agentic AI Foundation under the Linux Foundation, co-founded by Anthropic, Block and OpenAI.

• Does ChatGPT support MCP?+−

  Yes. ChatGPT apps and connectors are built on MCP servers; which features are available depends on the plan. Claude and Microsoft 365 Copilot also support remote MCP servers.

• Does Gemini or Google Search support MCP?+−

  Through Google's Connected Apps, announced in October 2026, a business can connect a cloud-hosted MCP server (or Android AppFunctions) to the Gemini app and Google Search. Access is a phased preview by application and varies by market.

• Is MCP secure?+−

  The protocol supports secure patterns (OAuth 2.1, scoped tokens), but security depends on the server you build: confirmations before committing actions, narrow scopes, minimal responses, logging and testing against prompt injection and tool poisoning.

• What is the difference between MCP and RAG?+−

  RAG retrieves documents to help a model answer. MCP lets a model call tools and read live data from your systems, including actions that change something. They work together: an MCP server can expose a search tool that does RAG underneath.

• Do I need an MCP server for my business?+−

  If customers or staff would benefit from an assistant doing tasks in your systems, such as booking, ordering or checking an account, an MCP server is the standard way to offer that. If you only need answers about public information, good content and AI search visibility come first.

Sources

• Anthropic: Introducing the Model Context Protocol
• Anthropic: Donating MCP and establishing the Agentic AI Foundation
• MCP blog: the 2026-07-28 specification release
• Google for Developers: Connected Apps
• Microsoft Learn: MCP Apps in Microsoft 365 Copilot
• OWASP: MCP tool poisoning
• Shopify: building for agents

• MCP
• AI agents

Ahmet Molon

Founder