MCP — Model Context Protocol

After my post about AI agents and MCP servers, several people asked me to explain these technologies in plain language. AI agents are an incredibly interesting subject, but all these harnesses are utterly baffling to non-specialists.

Let me begin with an example of an AI agent in action that was shown at the round table mentioned in that post.

Someone gave an AI agent his username and password for an electronic school journal. Yes, we all understand perfectly well that this is unsafe — personal data, leaks, hacking and so on — but, as the saying goes, nothing ventured, nothing gained. So he knowingly granted access and asked the agent to find out how his son was doing at school.

In ten seconds, the AI agent did the following:

• Found the electronic journal’s website online and logged in;
• Examined the site’s pages and worked out how to navigate its links, tabs, pages, tables, menus and assorted pop-ups;
• Searched every corner of the electronic journal and read all the available information;
• Analysed the information and returned a summary: “He is doing very well in these subjects; he had a setback in this one, but has since recovered; and in this subject he is consistently falling short — you need to work on it with him separately.”

Notice that the person did not visit the website, search it for marks in different subjects, write those marks down or plot charts to track the trends. The AI agent did all of that in ten seconds.

There is just one catch. The AI agent had to work out how the website was structured. First, that consumes tokens. Second, how can we be sure that the agent read all the available information, or that it did not forget some of what it had read earlier while navigating the site?

To minimise this risk, developers came up with MCP — the Model Context Protocol. With this protocol, a website provides AI agents with complete information in a form they can readily use. The agents do not need to work out how the site is structured: they immediately receive all the information about what they can do with it.

For example, a retail chain recently created an MCP server for its online catalogue and ordering system. One of the round-table participants told us that he connected his mother’s smart speaker to this MCP server. Now, while discussing the dinner menu with Alice, his mother can also ask Alice to order the missing ingredients for delivery. Alice finds the products in the retailer’s online catalogue and places the order herself. Fantastic!

In car rental, an MCP server would allow Alice to provide complete information about available vehicles, options and prices, and to book a suitable car for the travel dates without even opening an app.