What is MCP?

The Model Context Protocol (MCP) is an open standard that lets AI applications connect to external systems: databases, APIs, file systems, browsers, business tools, anything with an interface. It was released by Anthropic in November 2024, adopted by OpenAI in March 2025 and is now governed by the Linux Foundation. Think of it as USB-C for AI: one connector standard instead of a custom integration for every model and every tool.

Servers and clients

MCP splits the world into two roles. An MCP server is a program that exposes capabilities: a Postgres server exposes queries, a GitHub server exposes issues and pull requests, a filesystem server exposes files. An MCP client is the AI application that connects to those servers: Claude Desktop, ChatGPT, Cursor, Windsurf and a growing list of agent frameworks.

One client can connect to many servers at once. That is the whole point: instead of waiting for your AI tool to add a native integration, you plug in a server that already speaks the protocol.

Tools, resources and prompts

A server exposes three kinds of capability. Tools are actions the model can invoke, such as run a query or create an issue. Resources are data the client can read, such as a file or a schema. Prompts are reusable prompt templates the server offers. Most servers in the ecosystem are primarily tool providers.

Why it took over

Before MCP, every AI product had its own plugin format, so every tool vendor had to build the same integration several times. MCP replaced that with one protocol, open source and vendor-neutral. Within a year of release it had support from Anthropic, OpenAI, Google and Microsoft, more than a billion SDK downloads and tens of thousands of public servers.

The catch: quality varies wildly

Because anyone can publish an MCP server, the ecosystem ranges from production-grade software to abandoned weekend experiments. A server you connect to your AI client runs with real permissions on real data, so maintenance, documentation and trustworthiness matter. That is the problem MCPVault exists to solve: every listing carries a quality grade, maintenance signals and, for verified servers, proof that it actually responds.