import { z } from "zod";
import { McpAgent } from "agents/mcp";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
export class MyMCP extends McpAgent {
server = new McpServer({
name: "Authless Calculator",
version: "1.0.0",
});
async init() {
// calculator tool
this.server.tool(
"calculate",
"Performs basic arithmetic operations (add, subtract, multiply, divide) on two numbers.",
{
operation: z.enum(["add", "subtract", "multiply", "divide"]),
a: z.number(),
b: z.number()
},
async ({ operation, a, b,}) => {
try {
const processId = this.props.processId;
// userID & secret key
const userId: string | null = this.props.userId as string;
const secretKey: string | null = this.props.secretKey as string;
console.log(`[${processId}] UserID: ${userId}`);
console.log(`[${processId}] SecretKey: ${secretKey}`);
// calc operation
let result: number = 0;
switch (operation) {
case "add":
result = a + b;
break;
case "subtract":
result = a - b;
break;
case "multiply":
result = a * b;
break;
case "divide":
if (b === 0)
return {
content: [
{
type: "text",
text: "Error: Cannot divide by zero",
},
],
};
result = a / b;
break;
}
console.log(`[${processId}] result: ${result}`);
return { content: [{ type: "text", text: String(result) }] };
// error handling
} catch (error: any) {
console.error("ERROR:", error);
return { content: [{ type: "text", text: JSON.stringify({ status: "error", error_message: error.message }) }], isError: true };
}
}
);
}
}
export default {
fetch(request: Request, env: Env, ctx: ExecutionContext) {
// pid
const processId = Date.now().toString();
// userID & secret key from header
const userId: string | null = request.headers.get('X-UserID');
const secretKey: string | null = request.headers.get('X-SecretKey');
// context
ctx.props = { processId, userId, secretKey };
// routing
const url = new URL(request.url);
if (url.pathname === "/sse" || url.pathname === "/sse/message") {
return MyMCP.serveSSE("/sse").fetch(request, env, ctx);
}
if (url.pathname === "/mcp") {
return MyMCP.serve("/mcp").fetch(request, env, ctx);
}
return new Response("Not found", { status: 404 });
},
};
