MCP Client Definition: Host vs. Client vs. Server Explained

An MCP client is the connector inside an AI app that talks to one MCP server. It sends the server's requests, gets back its tools, data and prompts, and passes them to the AI. An app like Claude Desktop or Cursor creates one client for every server it connects to.

A simple way to picture it

Say you connect Claude Desktop to two servers: PostgreSQL and a filesystem server. Claude Desktop starts two clients. One holds the database connection. The other holds the file connection. If the database call fails, the file client keeps working.

Host, client and server

People mix these up, so here they are side by side:

• The host is the app you use: Claude Code, Claude Desktop, Cursor or ChatGPT. It can run several clients at once.
• The client is the piece inside the host that holds one connection to one server. It is the connector, not the chat window.
• The server is the program on the other end. See MCP server.

When someone says "Claude Desktop is an MCP client", they mean the host. It is a fair shortcut, and usually clear enough.

Why the difference matters

Knowing the roles helps you troubleshoot. A broken tool call or an over-broad permission belongs to one client and server pair, not to the whole app. It also means a client built to the MCP spec can talk to a new server with no code changes, including one hosted on the other side of the internet.

Which apps are MCP clients?

As of September 2026, Claude Code, Claude Desktop, Cursor and ChatGPT (through connectors) can all connect to remote servers. Each one has its own setup steps. See which AI clients support MCP for the current picture, or jump straight to adding a server to Claude Code.

Using a client with MCPifex

MCPifex serves each hosted server over Streamable HTTP at https://mcpifex.com/mcp. Any client that supports that transport can connect with an API key, so you don't install or run the server yourself. Pick one on the marketplace. The free plan covers 3 instances.