The Model Context Protocol (MCP) is a standard interface between an LLM application and the outside world — the tools it can call and the data it can read. Instead of hand-wiring every integration into every app, you build an MCP server once and any MCP-compatible client can use it. It is a common plug for tool calling.
Why it matters in production
Before a standard, every model-to-tool connection was bespoke: new glue code per app, per model, per tool. MCP turns that into reusable servers with a defined contract. The value is not novelty — the underlying capability is still tool calling — it is that the integration becomes portable and testable instead of a tangle of one-offs.
The common mistake
Assuming the protocol fixes tool design. MCP standardizes how a tool is exposed, not whether the model can use it well. A server that dumps forty overlapping, vaguely-described tools is just as confusing to a model as forty raw API calls — now with extra ceremony. The hard part, designing a tool catalog the model can reason about, does not go away because you wrapped it in a standard.
How we actually use it
We build MCP servers with a small, sharply-described tool set, treat each tool's schema as the model-facing contract it really is, and put guardrails on anything with side effects. We wrote up the concrete build in inside an MCP tool server, and where MCP fits against plain retrieval and full agents in MCP vs RAG vs agents.