MCP terms, in plain English

MCP (Model Context Protocol)

An open protocol that lets AI assistants use external tools and data through a standard interface. Instead of every app building custom integrations, a client speaks MCP to any server that implements it.

Plain-English introduction →

MCP server

A program that gives an assistant a specific capability: querying a database, controlling a browser, reading files, calling an API. It advertises tools the assistant can invoke and returns their results.

Browse every server we track →

MCP client

The app the assistant lives in, such as Claude Desktop, Claude Code, Cursor, or VS Code. The client connects to servers, lists their tools, and calls them on the assistant's behalf.

Setup guides per client →

Tool

A single action a server exposes, with a name and typed inputs: search_issues, read_file, run_query. Assistants decide when to call a tool; the server executes it and returns the result.

Resource

Read-only content a server can hand to the assistant as context, like a file, a document, or a record. Where a tool is an action, a resource is material.

Prompt (MCP)

A reusable prompt template a server ships alongside its tools, which clients can surface for one-click use. Not to be confused with the message you type.

Transport

How client and server talk. Local servers usually run as a child process over stdio; remote servers speak HTTP, either streamable HTTP or the older SSE style.

stdio server

A server your client starts as a local process and talks to over standard input and output. It runs on your machine, with your permissions, and stops with your session.

Remote MCP server

A server hosted by a provider that you connect to by URL. Nothing to install or update locally; auth is usually an API key or OAuth.

The best remote servers, probed nightly →

MCP registry

The official public index of MCP servers where authors register their projects. It is the discovery layer this site syncs from every night; quality and maintenance signals are layered on top by us.

Install config

The snippet that wires a server into your client, usually a JSON entry naming the command to run or the URL to reach. Each client keeps it in its own file under its own top-level key; every server page here renders the exact block per client.

Environment variables

Credentials and settings a server needs before it runs, like an API key or a database URL. Server pages on this site list exactly which variables a project's own documentation declares, and nothing more.

Collection (monorepo)

One repository shipping many servers, each in its own subfolder. We give each member its own page when it has its own real documentation, grouped under a collection hub.

Verified (on this site)

What our nightly sweep actually checked: the registry entry synced, the repository's activity read, package installs counted, and remote endpoints probed. Every page states when it was last checked.

The full recipe →