The Model Context Protocol is an open standard for connecting a language model to the systems that hold real work: file stores, databases, ticketing tools, internal APIs. Before it existed, every integration was bespoke. A team wiring a model into its CRM wrote glue code that no other team could reuse, and each new data source restarted the effort.
MCP splits that problem into two halves. An MCP server exposes a capability, such as "search these documents" or "create this issue". An MCP client, usually the application hosting the model, speaks the same protocol and can talk to any server without knowing how it was built.
The practical effect is reuse. One MCP server for a company wiki serves a coding assistant, a support agent, and an internal chatbot at the same time. Server authors describe their tools once, in a machine-readable form the model reads at runtime, so the model can decide which tool fits the request.
For teams building agents, MCP is usually where retrieval and action stop being demo code and start being infrastructure.