What is an MCP server?
An MCP server is a program that exposes tools, data, and prompts to AI assistants using the Model Context Protocol, an open standard. It lets an assistant like Claude query your systems through one defined, permissioned interface instead of needing a custom integration built for each assistant.
In context
Before MCP, connecting an assistant to an internal system meant building an integration specific to that assistant. Connect three assistants to four systems and you have twelve integrations to maintain. MCP standardises the interface so a server you write once works with any compatible client.
A server advertises three kinds of thing: tools the assistant can call, resources it can read, and prompts it can use. The assistant discovers what is available at connection time, which is why clear tool names and descriptions matter more than they look like they should.
Servers run either locally over stdio, which suits developer tooling, or remotely over HTTP for shared internal use. Remote deployment is where the security design matters: per-user identity rather than a shared service account, read-only by default, and an audit log of every call.
A concrete example
Internal data in an engineer editor
A company runs an MCP server exposing three read-only tools: query the analytics warehouse, look up a Jira ticket, and fetch internal API documentation. An engineer working in Claude Code asks what the current schema for the orders table looks like and gets the real answer, filtered by their own database permissions, without leaving the editor or pasting anything into a chat window. Every call is logged with who made it.
Common questions
Is MCP just an API?
It is a standard layer on top of whatever API you already have. The difference is that MCP describes tools in a way an AI assistant can discover and reason about, which an ordinary REST endpoint does not do.
Is it safe to connect to production data?
It depends entirely on how the server is built. A well-built one is read-only by default, carries the identity of the person asking through to the underlying system, exposes only the operations you intend, and logs every call. One built without those is a genuine liability.
Who can use an MCP server once it exists?
Any MCP-compatible client, which includes Claude Desktop and Claude Code, subject to whatever authentication you put in front of it. That portability is most of the reason to use the standard rather than a bespoke integration.
We build this, not just define it.
MCP server is part of mcp server development. See what that looks like as an engagement.