MCP vs Plugins
The word plugin is broad. It usually describes an extension packaged for one application or platform. MCP is different: it is a protocol that defines how compatible hosts and servers communicate.
Vendor-specific extension vs shared protocol
A plugin system often has its own manifest, lifecycle, permissions, marketplace, UI conventions, and packaging rules. Those can be excellent for the host they target, but the extension is commonly coupled to that ecosystem.
An MCP server is intended to be reusable across compatible clients. The server exposes capabilities according to the MCP contract rather than according to one application's proprietary plugin API.
Can an application still have plugins?
Yes. A host can implement a plugin marketplace where one kind of plugin happens to be an MCP server or connector. The concepts are not mutually exclusive.
Why the distinction matters
For teams building internal AI capabilities, a protocol boundary can reduce lock-in. The same MCP server may be consumable by a coding assistant, a desktop AI application, or an internal agent runtime, subject to each client's supported features and security model.