MCP App vs MCP Server vs Connector: Definitive Terminology Guide for 2026

MCP server, MCP app, and connector are distinct terms that refer to different layers of the same system. An MCP server is the running process that implements the Model Context Protocol over JSON-RPC 2.0. This layer is most relevant to engineers working on the technical implementation. MCP app is the product term for the user-installable artifact built on top of the MCP server.

This layer focuses on the user experience, branding, distribution, and monetization. Connector is what Claude calls an installed MCP app inside its product. This term is used by Claude for its specific implementation of the MCP app. Understanding these different layers is crucial to avoid confusion and miscommunication in product teams.

The Model Context Protocol is a JSON-RPC 2.0-based protocol introduced by Anthropic in November 2024. It defines the communication between clients and servers, including capabilities negotiation, tool operations, resource reading, and prompts. The three primitives of the MCP protocol are tools, resources, and prompts. Tools are operations the agent can invoke, each with a name, description, and input schema.

Resources are data the agent can read, with a URI, name, description, and MIME type. Prompts are templated user-facing prompts offered by the server. MCP-powered software involves at least three distinct objects: the protocol implementation (MCP server), the capability surface (MCP app), and the user-installable experience (connector, plugin, app, etc.).

These terms refer to different layers of the system and can be used interchangeably depending on the context. However, using the correct term in the right layer is essential to avoid stalling roadmaps and causing confusion.