What is an MCP server?
An MCP server is a connection that lets an AI assistant use another product through a shared plug, instead of a one-off integration for every app.
MCP stands for Model Context Protocol. You do not need the expansion to use one. Think of it as a standard outlet. Your AI app is the plug. The server is the thing on the other side: search, a helpdesk, a CRM, a design file, a spreadsheet in the cloud. Because the outlet is standard, Claude, Cursor, VS Code, and other apps can talk to the same server without each vendor building a private connector.
A skill is different. A skill is a folder of instructions the assistant reads before it works. It can say "when someone asks for a landing page, follow these checks." It does not, by itself, log into anything. An MCP server is the login, or the pipe, that can fetch or change data somewhere else. Many useful setups are one skill plus one server. Many accidents are a server that can write, connected on a Friday afternoon.
What actually happens
You add the server in the AI app's settings. Sometimes that is an install button. Sometimes it is a web address you paste. Sometimes it is a command a technical teammate runs. The app then shows a list of tools, which are the actions the server is willing to perform: search the web, fetch a ticket, create an invoice, post a chat message.
When you ask for something, the assistant picks a tool and fills in the details. A careful app asks you to confirm before a tool that changes data. Not every app does, and not every server marks its tools clearly. Read the permissions on the listing, then read the confirm dialog, before you approve an action you cannot undo.
Read, write, and whose login
The important question is not "is this AI?" It is "whose account is this, and can it change anything?" A web search server reads public pages. A helpdesk server may read customer conversations. A finance server may create invoices. Hosted servers from the product company usually sign in as a person at that company, and then they can do whatever that person can do. If you connect an admin account, the assistant is an admin.
Prefer a person with ordinary access, a sandbox, or a demo company when the product has one. Turn off write tools when the server lets you. Help Scout's community server, for example, keeps replies off until you opt in. Zapier is the opposite shape: one connection can reach many other apps, so the risk is the width, not the chat window.
A safe first try
Do not start with your inbox, your ledger, or your customer queue. Start with a public web search. Ask for three sources and open the links yourself. If the assistant cannot show a URL, it is not ready for a decision. After that, try a read-only question against a system you already know: "summarize this page" or "list my open tickets," and compare the answer with the screen.
SkillsByRole marks every current listing untested. That means we wrote the summary from the publisher's docs and have not run the server. The source link on each listing is the check when a button has moved.
Next: how to install a skill, or go back to the directory.
