What is Model Context Protocol (MCP) and how to use it
AI assistants previously required custom integrations for every tool or data source you wanted them to access. If you wanted an assistant to interact with a specific software environment, you had to maintain separate connection logic for each host application. The Model Context Protocol defines a single open standard for connecting AI apps to external tools. A server declares what it can do, the…
The Model Context Protocol (MCP) is an open standard that enables AI assistants to access external tools and data sources in a standardized way. Before MCP, each AI application required custom integrations for every tool or data source it needed to interact with. MCP defines a single protocol for connecting AI apps to external tools, simplifying the process.
The architecture of MCP consists of three parts: the host (the AI application), the server (a program exposing specific tools or data), and the model (the AI assistant). The model never communicates directly with the server; instead, it relies on the host to act as a middleman. Communication between the model and the server occurs via JSON-RPC, which travels either over stdin/stdout or through HTTP endpoints.
A real-world example of MCP in action is the Roblox Studio integration. An open-source server called HerdBuilderEstimate/roblox-studio-mcp bridges Roblox Studio and AI coding assistants. It communicates via WebSockets and standard input/output, and a Lua plugin handles the operations within the Roblox Studio API. This server allows language models to understand game architecture, generate Lua scripts, and automate developer tasks.
It is compatible with various AI assistants, including Claude Desktop, Cursor, and ChatGPT, through appropriate adapters.
To use an existing MCP server, you add it to your AI assistant's configuration file. For the Roblox Studio server, you would add the server details to the `mcpServers` object in your client's configuration file, such as `claude_desktop_config.json`. Restarting the AI assistant after updating the configuration allows the host to discover the server's tools and automatically find open Studio sessions.
While MCP provides a standardized way to connect AI applications to external tools, the security of the server implementation is crucial. The server defines the security boundaries, not the protocol itself. If the server exposes destructive tools, the AI host can use them. For instance, in the Roblox Studio integration, you must have edit access to the project for the tools to work.
To prevent unwanted changes, you can run the server in safe mode by setting the environment variable `RBX_MCP_SAFE_MODE` to true, which disables destructive actions like object deletion.
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- MCP Explained: how the Model Context Protocol works mcp-explained.com
