Guides

What is an MCP server?

An MCP server is a program that gives an AI agent tools it can call, such as searching a CRM, sending an invoice or booking a meeting. MCP, the Model Context Protocol, is the open standard for how agents and these servers talk, so one server works in Claude, ChatGPT, Cursor and every other app that supports it.

By Amelia Cardona HernandezUpdated October 21, 2026Sources checked October 15, 20266 min read

MCP in two minutes

Anthropic released the Model Context Protocol as an open standard on November 25, 2024, to connect AI assistants to the systems where a business keeps its data.¹ On December 9, 2025, it donated the protocol to the Agentic AI Foundation, a fund under the Linux Foundation that Anthropic, Block and OpenAI co-founded.² Anthropic counted more than 10,000 active public MCP servers at that point, and ChatGPT, Cursor, Gemini, Microsoft Copilot and Visual Studio Code had adopted the protocol.²

When a tool you use publishes an MCP server, every agent that speaks MCP can use it. Nobody has to build one integration for Claude, another for ChatGPT and a third for Cursor.

Hosts, clients and servers

The protocol's architecture page names three participants.³

The host is the AI application, such as Claude Desktop, ChatGPT or Cursor.
A client is the connection the host keeps to one server. The host opens one client for each server it uses.
The server is the program that provides tools and context.

Say Dana runs Halverson Cycle & Repair, a bike shop with a repair workshop in Portland. She adds two servers to Claude, one for her customer records and one for her calendar, and Claude opens a client for each. When she asks it to book Rachel's bike fitting for Saturday and note it on her record, Claude calls a calendar tool through one connection and a CRM tool through the other.

What a server offers

A server can expose three kinds of things.³

What	What it is	A business example
Tools	Functions the agent calls to do something	Send an invoice, book a meeting, reply to a ticket
Resources	Data the agent reads for context	A customer record, a price list, a file
Prompts	Reusable templates for a task	The standard reply to a refund request

Tools matter most for running a business. Each tool has a name, a description and the inputs it accepts, and the agent reads them to choose the tool that fits a request. In the current version of the protocol, dated July 28, 2026, a client can first ask a server what it supports, then lists its tools with tools/list and runs one with tools/call.³

Local servers and remote servers

MCP has two ways to connect:

Local servers run as a program on your own computer, started by the AI app over standard input and output. They suit developers and files on your machine, and each one usually serves a single client.³
Remote servers run at an internet address, such as https://mcp.stripe.com, over Streamable HTTP. Many clients share one, and nothing is installed on your computer.^3,6

Nine of the eleven vendor servers in our list for small businesses are remote. A remote server that holds private data signs you in, and the specification builds this on OAuth 2.1: the server tells the client where to sign in, you approve the access on the vendor's own page, and the client receives a token that you can revoke later.⁴ Some servers take an API key in a header instead, which suits an agent that runs without a person present, like a coding agent in a terminal.⁶

How to connect a server to your agent

Every app has its own place for MCP servers. These are the places their makers document; our page for each agent has the exact steps and links the source.

Agent	Where you add a server
Claude	Customize, Connectors, Add custom connector, then paste the address
ChatGPT	chatgpt.com/plugins, the + button, Add custom MCP server
Grok	grok.com/connectors, New Connector, Custom
Claude Code	`claude mcp add --transport http` with a name and the address
Cursor	`.cursor/mcp.json`
Codex	`~/.codex/config.toml`
Gemini CLI	`~/.gemini/settings.json`
Hermes Agent	`~/.hermes/config.yaml`
OpenClaw	`openclaw mcp add`

In Claude, ChatGPT and Grok you paste an address and sign in once. ChatGPT allows custom MCP servers that take actions on its Business, Enterprise and Edu plans, and read-only ones on Pro.¹² The coding agents read a configuration file or take a command, usually with an API key kept in an environment variable. Claude's own settings for this are in Claude connectors.

Where to find MCP servers

Start with the software you already use. Stripe, PayPal, Square, HubSpot, Notion, Asana and Intercom run their own remote servers, and Intuit and Xero publish servers for QuickBooks and Xero on GitHub. Our list of the best MCP servers for small business has the address, the sign-in and the catch for each.

The official MCP Registry lists public servers in a standard server.json format and verifies each publisher's namespace through GitHub, DNS or HTTP checks. It is in preview, backed by Anthropic, GitHub, PulseMCP and Microsoft, and its maintainers say it may change before general availability.⁵

What to check before you connect one

A server acts with the access you give it. Check five things first.

Who runs it. A server published by the vendor itself is the safest start.
What it can change. Tools that read are low risk. Tools that send, pay, refund or delete need care.
How it signs in. With OAuth you can see and revoke the access on the vendor's side; Stripe, for example, lists each authorized client under OAuth sessions.⁶
Whether it asks first. Claude asks for your approval before it sends, replies to or forwards a Gmail message, unless an owner on a Team or Enterprise plan changes that.⁷ Stripe recommends turning on your client's tool approval setting so you can review each call before it runs.⁶
What else it reads. A web page, an email or a file can carry text written to steer an agent. OpenAI's help center describes a malicious comment that tells an agent to fetch a password reset code from Gmail and send it to a website.⁸ Connect only the servers a task needs, and keep risky tools behind approval.

What an MCP server costs

The protocol is free and open source. Each server is priced by whoever runs it:

Many vendors include their server with your account. Zapier includes Zapier MCP in every Zapier plan,⁹ and each successful tool call uses two tasks from your plan.¹¹ We compare it with six alternatives in Zapier MCP alternatives.
Some servers charge per call. On Conecto, our product, reading your own data is free up to a million reads a month, a change to a record costs $0.01, and a call that fails costs nothing.¹⁰
Your agent's own usage is billed separately, through the Claude or ChatGPT plan you already have.

Questions

Is an MCP server the same as an API?

An MCP server often sits on top of an API, as Stripe's does.⁶ A program calling an API has to be written for that vendor's endpoints, while an MCP server describes its tools in a form any agent can discover and call without code written for that vendor. MCP vs API compares the two side by side.

Do I need to code to use an MCP server?

You don't for remote servers. In Claude and Grok you paste the server's address and sign in, and in ChatGPT you do the same on a Business, Enterprise or Edu plan.¹² Local servers and coding agents take a configuration file or a command.

Can an agent use an MCP server without asking me?

That depends on the app and the server. Claude asks before it sends email through its Gmail connector,⁷ many apps can ask before every tool call, and a server can hold chosen actions, like refunds, until a person approves them.

What is the difference between an MCP server and a skill?

A skill is a set of written instructions an agent loads when a task needs them, usually a SKILL.md file. An MCP server gives the agent tools to act. They work together: Conecto's SKILL.md tells an agent how to sign up and pay, and its MCP servers give it the tools.¹⁰

Who owns MCP?

Since December 9, 2025, the Agentic AI Foundation, a directed fund under the Linux Foundation co-founded by Anthropic, Block and OpenAI.²

Sources

We read these pages on October 15, 2026. Each number in the guide links to the page behind that sentence.

Conecto publishes this guide and sells business tools for AI agents. How we write our guides. To report a mistake, write to hello@conecto.chat.

Written by Amelia Cardona Hernandez, Co-founder of Conecto. LinkedIn