MCP speaks JSON-RPC 2.0. Implement handle(request, tools) for two methods:

tools/list: returns { tools: [{ name, description, inputSchema }] }.
tools/call: runs params.name with params.arguments and returns { content: [{ type: "text", text }] }.

Errors: unknown method gives code -32601, unknown tool gives -32602. A tool that throws is not a protocol error: return a normal result with isError: true, so the model can read it. A request without id is a notification: return null.

Exercises in this module

Terminal