MCP Simulator
The Model Context Protocol (MCP) is how an AI model talks to outside tools — a database, your files, GitHub. It’s hard to picture from a definition, so watch it happen: pick a mock server, hit run, and follow the model through the four steps of a tool call.
A read-only database the model can query with SQL.
Tools this server exposes
query — Run a read-only SQL query and return the rows.The model reads the server’s tool list, sees a `query` tool that runs SQL, and decides to use it. It writes the SQL itself from your plain-English request.
The model sends a JSON-RPC tools/call over MCP — naming the tool and its arguments.
The MCP server runs the query and returns the result as content the model can read — not a screenshot, real data.
The model turns the rows into a normal reply: “There are 3 users with active subscriptions — Ada Lovelace, Alan Turing, and Grace Hopper.”
This is a visual simulation of the Model Context Protocol handshake — the JSON is real MCP, the data is mocked. No live model or server is contacted.
Want the full explanation? Read What Is MCP? for the plain-English version, or browse our MCP explainers and server roundups.