MCP client vs MCP server: which one do you install?
The MCP client is the app you type into: Claude Desktop, ChatGPT, Cursor. The MCP server is the thing you connect it to, like Gmail, Slack, or a folder of files. You almost never build a client. You install servers, and the app you already use handles the rest.
MCP client vs MCP server at a glance
| Aspect | MCP client | MCP server |
|---|---|---|
| What it is | The AI app you talk to | A connector holding one set of tools |
| Examples | Claude Desktop, ChatGPT, Cursor | Gmail, Slack, a folder on your laptop |
| Who makes it | The AI company | The tool company, or you |
| Where it runs | On your screen | Your machine or the tool company's |
| What you do | Open it | Add it, approve what it can touch |
The naming is the whole problem
"Server" makes people picture a machine in a data center. Most MCP servers are not that. A Gmail connector can run quietly on your own laptop with no page to visit. One engineer summed the confusion up on Hacker News: an MCP server is a server to the AI app, but it is a client to the thing it connects to. Both readings are true, which is why the words feel backwards.
Second surprise: the AI app opens one client per server. Add 5 connectors and the app is holding 5 separate connections, each with its own permissions and its own list of tools. Switching one off leaves the other 4 running.
Which one you actually set up
Servers. Almost always servers. Adding Gmail to Claude Desktop means adding a server, and each server offers up to three things: tools it can run, files it can read, and ready-made prompts. Building a client means building the chat app itself.
For Zapier and n8n users
n8n ships both, under names one word apart. The MCP Client Tool node lets an agent call someone else's connector. The MCP Server Trigger node does the reverse: it publishes your workflow so other AI apps can call it. Zapier MCP is a server, covering 30,000+ actions across 9,000+ apps.
Start by adding servers. Build one only when you want your own workflow callable from other AI apps.
Last updated: Sep 5, 2026