MCPmatic

What is the Model Context Protocol (MCP)?

Published · Updated · Written against MCP spec 2026-07-28

The Model Context Protocol is an open protocol for connecting AI applications to outside data and tools. The specification describes it as a standardised way to connect LLM applications with "the context they need".

The short version#

Without a shared protocol, every AI app needs custom code for every service it talks to. MCP defines one way for an AI application to discover what a service offers and call it, so a server written once can be used from any MCP-compatible app.

Hosts, clients and servers#

  • Host: the AI application the person uses, for example a desktop chat app or a code editor. It coordinates one or more clients.
  • Client: a component inside the host that holds a connection to one server and gets context from it.
  • Server: a program that provides context and actions. It can run on your machine or remotely.

The MCP docs give Visual Studio Code as an example host: it creates a client for each server it connects to.

What a server can offer#

  • Tools: actions the model can call, such as querying a database or calling an API. Each tool has a name, a description and a JSON Schema for its input (see the tool schema reference). Tools are "model-controlled": the model decides when to call them. The spec says there SHOULD always be a human in the loop who can deny a call.
  • Resources: data the client can read, identified by URI, such as files or records.
  • Prompts: reusable prompt templates the user can pick.

Transports#

  • stdio: the host starts the server as a local process and talks over standard input and output. This is how most desktop setups run local servers.
  • Streamable HTTP: the client sends HTTP POST requests to a remote server, with optional Server-Sent Events for streaming. This is used for hosted servers and supports normal HTTP authentication. The MCP docs recommend OAuth for obtaining tokens.

Which version is current?#

The current stable specification is 2026-07-28, released on 28 July 2026. Its biggest change is a stateless core: no more initialize handshake or sessions. See what changed in 2026-07-28.

Where to go next#

Frequently asked questions#

Is MCP only for Claude?

No. MCP is an open protocol. The MCP architecture docs use Visual Studio Code, Claude Desktop and Claude Code as example hosts, and Cursor documents its own MCP support.

Is an MCP server the same as an API?

Usually it wraps one. An MCP server describes its actions as tools with JSON Schemas so an AI application can discover and call them in a standard way. Many servers call an existing HTTP API behind the scenes.

Do I need to write a server to use MCP?

No. You can connect existing servers to an MCP host using its config file. See add an MCP server to Claude Desktop and Cursor.

Sources#

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