# What is an MCP server?

Plain-language definition of Model Context Protocol servers and why install choices matter.

## Short answer
An **MCP server** is a program that exposes tools, data, or actions to an AI client through the Model Context Protocol. Clients (Cursor, Claude, VS Code, custom agents) connect to it so the model can use real systems — files, APIs, browsers, tickets — under whatever permissions that server implements.

## Why installs are a trust decision
Connecting a server is closer to installing a plugin with credentials than bookmarking a website. A malicious or abandoned server can leak data, run unexpected tools, or simply break your agent loop.

## What the census checks
We do **not** replace reading the server’s code. We publish public evidence: registry identity, repo/package health, hosted endpoint liveness, collisions, and a scored factor trail. Start at [lookup](/lookup).

## What this is not
Not a full security audit. Not an endorsement of any vendor.