How to Install an MCP Server: Claude, ChatGPT & Gemini

What about Claude Fable 5.2?

Claude Fable 5.2 came out on November 9, 2026 and Claude Code already uses it as its default Fable model. You don't need to do anything special: MCP servers are added to the app (Claude, Claude Code), not to the model. The ones you already had are still there when you switch to Fable 5.2, and the ones you add now will work with whichever model you choose.

Install a remote MCP in Claude

This works for claude.ai and the Claude app:

1. Open Customize → Connectors. 2. Click + Add and choose Add custom connector. 3. Type a name you'll recognise, paste the server's address and click Continue. 4. If the server doesn't need an account, choose No sign in, click Continue and then Add. If it does, sign in when prompted.

Then, in a chat, click + at the bottom left → Connectors and turn it on. On the free plan you can have one custom connector.

Install a remote MCP in ChatGPT

ChatGPT now calls custom MCP servers plugins, and you need a paid account:

1. Go to chatgpt.com/plugins. 2. Click + and choose Add custom MCP server. 3. Type a name and a description, and paste the address under Connection. 4. If it doesn't need an account, don't set up authentication. Accept the warning and click Create as a plugin.

To use it, type @ in a new chat and pick the plugin.

Install an MCP in Gemini (Gemini CLI)

The Gemini app doesn't support custom servers yet, but Gemini CLI does. It runs in the terminal and needs a Gemini Code Assist license: since June 2026 it has no free tier.

gemini mcp add --transport http -s user context7 https://mcp.context7.com/mcp

Open Gemini CLI and type /mcp to check it's there. Mcpteca listings have this command ready with each server's address.

Install an MCP in Claude Code

Claude Code is Anthropic's coding assistant for the terminal (compare it with Codex, Gemini CLI and others in AI coding CLIs compared). A remote server is added with one command:

claude mcp add --transport http name https://server-address

And a local one by putting its start command after --:

claude mcp add name -- npx -y server-package

By default the server is only available in the folder you're in. Add --scope user to have it in all your projects. claude mcp list shows the ones you have.

Install an MCP in VS Code

In Visual Studio Code open the Command Palette and choose MCP: Add Server. You can also write it by hand in .vscode/mcp.json (just for that project) or in your user configuration (MCP: Open User Configuration). Note that VS Code uses the servers key:

{
  "servers": {
    "context7": {
      "type": "http",
      "url": "https://mcp.context7.com/mcp"
    }
  }
}

For a local one, use "type": "stdio" with command and args, as in Claude Desktop.

Install an MCP in Cursor

Cursor reads ~/.cursor/mcp.json (for all your projects) or .cursor/mcp.json (for just one). It uses the mcpServers key:

{
  "mcpServers": {
    "context7": {
      "url": "https://mcp.context7.com/mcp"
    },
    "playwright": {
      "command": "npx",
      "args": ["-y", "@playwright/mcp@latest"]
    }
  }
}

Summary by assistant

Check that it works

Ask a question only the server can answer. With Context7, for example: "Use Context7 to look up the current documentation for this library". The assistant should ask your permission to use the tool and answer with up-to-date documentation. If it answers from memory without asking, the server isn't active: check that it's turned on in the chat.

If something goes wrong

• It doesn't show up: quit the app completely (also from the system

tray) and open it again.

• Error when saving the file: almost always a missing comma or an extra

brace. Paste the file into a JSON validator.

• `npx` not found (`ENOENT`): Node.js isn't installed or the app can't

see it. Install it and restart your computer.

• Windows paths: inside the JSON, write double backslashes

(C:\\Users\\...).

• It asks you to sign in: that's normal for servers of services with an

account; follow the steps your assistant shows.

Below you'll find servers to practise with, and Context7 ready to install.