Reference

MCP hub

Learn how an AI app connects to files, websites, and other tools, and choose what each connection may access.

MCP expands what an AI app can reach. Choose which files, accounts, and actions each server may access.

MCP in plain English

Model Context Protocol (MCP) lets an AI app connect to tools and information. For example, a file connector can let it read a folder you choose.

Host, client, server

The host is the AI app. Its client is the connector. The server is the program that provides access to files, web pages, or another service.

Tools, resources, prompts

Tools perform actions, such as searching files. Resources provide information to read. Prompts are reusable instructions.

Local and remote servers

Local servers run on your computer. Remote servers run elsewhere and may receive your requests or files. Check the permissions and data destination before connecting.

stdio and Streamable HTTP

With stdio, the app starts a program and communicates directly with it. Streamable HTTP connects over a network. Check who can connect and whether a sign-in is required. Older servers may offer HTTP+SSE, which many apps no longer connect to directly; the MCP guide covers the bridge.

What a connection looks like

A host such as LM Studio reads a configuration file and starts each server as a subprocess. For the filesystem server, the command from the directory is:

npx -y @modelcontextprotocol/server-filesystem /path/to/allowed/folder

The host runs one client for each server. The client talks to the server through the program's standard input and output (stdio), so nothing listens on a network port. The filesystem server serves only the folder you pass, so give it the narrowest folder that does the job. The program still runs with your account's permissions.

A Streamable HTTP server has an address instead. Before you connect, find out who runs it, whether it needs a sign-in, and whether it listens only on 127.0.0.1 or on every network interface.

The file that holds this command differs by app. The MCP guide shows where it goes in LM Studio and Open WebUI.

Security warnings

File servers can read or write local data inside their configured scope.
Developer servers may execute commands or access private repositories.
API-key and OAuth servers can expose secrets if permissions are too broad.
A remote server may reach private network addresses or pass along your access credentials. Only give it the access it needs.
Localhost services can become network-exposed if binding, Docker ports, or firewall settings are wrong.
Check the exact server’s permissions and code before giving it sensitive files or credentials.

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