Tool use & MCP
How is the Model Context Protocol built?
MCP has three roles: a host (the AI application), a client inside it, and a server that exposes tools, resources, and prompts. The pieces talk over JSON-RPC, and the standard now spans OpenAI and Google.
Under the hood, MCP has three roles: a host (the AI application), a client inside the host, and a server that exposes capabilities. A server can offer three kinds of thing: tools the model can call, resources it can read, and prompts it can reuse. The pieces talk over JSON-RPC.[1]
By 2026 the standard had spread well beyond its origin, with OpenAI and Google supporting it and a large ecosystem of public servers. That adoption is what turns MCP from a nice idea into a default.
References
- Model Context Protocol — Architecture — Model Context Protocol