// src/index.ts
import { McpAgent } from "agents/mcp";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
// Utility: safe extraction of IP address (from request headers, if available)
function getClientIp(request: Request): string | null {
// Prefer standard headers like CF-Connecting-IP, X-Forwarded-For
// Workers provides CF-Connecting-IP on production
const cfIp = request.headers.get("CF-Connecting-IP");
if (cfIp) return cfIp;
// Try X-Forwarded-For
const xff = request.headers.get("X-Forwarded-For");
if (xff) return xff.split(",")[0].trim();
return null; // Unknown
}
// Utility: call a free geoip Web API
async function lookupTimezoneByIp(ip: string): Promise<string | null> {
try {
// Use ip-api.com (has a Cloudflare-friendly free endpoint)
const resp = await fetch(`https://ip-api.com/json/${encodeURIComponent(ip)}?fields=status,message,timezone`);
const data = await resp.json<any>();
if (data?.status === "success" && typeof data.timezone === "string") {
return data.timezone;
}
return null;
} catch (error) {
console.error("GeoIP lookup failed", error);
return null;
}
}
// Main MCP Agent
export class MyMCP extends McpAgent {
server = new McpServer({
name: "Timezone Finder",
version: "1.0.0"
});
async init() {
this.server.tool(
"get_timezone", // Tool name for MCP clients
{
// no input parameters
},
async (_params, context) => {
// Try to access the request from context (for remote MCP connections)
let ip: string | null = null;
// 'context.request' is only available in HTTP transport (MCP supports local/stdio too)
//@ts-ignore
const req: Request | undefined = context?.request as Request | undefined;
if (req) {
ip = getClientIp(req);
}
// If no IP in request, client likely not remote or header missing
if (!ip) {
return {
content: [
{
type: "text",
text: "Cannot determine IP (only available in HTTP/SSE remote calls), timezone: unknown"
}
]
};
}
// Lookup timezone
const tz = await lookupTimezoneByIp(ip);
if (tz) {
return {
content: [
{
type: "text",
text: `Your timezone is: ${tz}`
}
]
};
} else {
return {
content: [
{
type: "text",
text: "Could not determine timezone for your IP address."
}
]
};
}
}
);
}
}
export default {
fetch(request: Request, env: Env, ctx: ExecutionContext) {
const url = new URL(request.url);
// Support both SSE and Streamable HTTP transports for MCP
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);
}
// Health or demo endpoint
if (url.pathname === "/timezone") {
const ip = getClientIp(request);
return lookupTimezoneByIp(ip || "").then(tz =>
Response.json({ timezone: tz ?? null, ip: ip ?? null })
);
}
return new Response("Not found", { status: 404 });
}
};
