feat: Add md tracking for AI usage analytics

docs/site/app/[lang]/llms.md/[[...slug]]/route.ts

@@ -1,10 +1,11 @@
 import { notFound } from "next/navigation";
 import { getLLMText, source } from "@/lib/geistdocs/source";
+import { trackMdRequest } from "@/lib/md-tracking";
 
 export const revalidate = false;
 
 export async function GET(
-  _req: Request,
+  req: Request,
   { params }: RouteContext<"/[lang]/llms.md/[[...slug]]">
 ) {
   const { slug, lang } = await params;
@@ -14,6 +15,17 @@ export async function GET(
     notFound();
   }
 
+  // Track markdown request (fire-and-forget)
+  const userAgent = req.headers.get("user-agent");
+  const referer = req.headers.get("referer");
+  const acceptHeader = req.headers.get("accept");
+  void trackMdRequest({
+    path: `/llms.md/${slug?.join("/") ?? ""}`,
+    userAgent,
+    referer,
+    acceptHeader
+  });
+
   return new Response(await getLLMText(page), {
     headers: {
       "Content-Type": "text/markdown"

docs/site/app/[lang]/llms.txt/route.ts

@@ -1,18 +1,30 @@
 import type { NextRequest } from "next/server";
 import { source } from "@/lib/geistdocs/source";
+import { trackMdRequest } from "@/lib/md-tracking";
 
 export const revalidate = false;
 
 const TURBO_SLOGAN =
   "Turborepo is a build system optimized for JavaScript and TypeScript, written in Rust.";
 
 export const GET = async (
-  _req: NextRequest,
+  req: NextRequest,
   { params }: RouteContext<"/[lang]/llms.txt">
 ) => {
   const { lang } = await params;
   const pages = source.getPages(lang);
 
+  // Track markdown request (fire-and-forget)
+  const userAgent = req.headers.get("user-agent");
+  const referer = req.headers.get("referer");
+  const acceptHeader = req.headers.get("accept");
+  void trackMdRequest({
+    path: "/llms.txt",
+    userAgent,
+    referer,
+    acceptHeader
+  });
+
   const links = pages
     .sort((a, b) => a.url.localeCompare(b.url))
     .map((page) => {

docs/site/lib/md-tracking.ts

@@ -0,0 +1,53 @@
+const MD_TRACKING_URL = process.env.MD_TRACKING_URL;
+const MD_TRACKING_API_KEY = process.env.MD_TRACKING_API_KEY;
+
+interface TrackMdRequestParams {
+  path: string;
+  userAgent: string | null;
+  referer: string | null;
+  acceptHeader: string | null;
+}
+
+/**
+ * Track a markdown page request to the feedback-app analytics.
+ * Fire-and-forget: errors are logged but don't affect the response.
+ */
+export async function trackMdRequest({
+  path,
+  userAgent,
+  referer,
+  acceptHeader
+}: TrackMdRequestParams): Promise<void> {
+  if (!MD_TRACKING_URL || !MD_TRACKING_API_KEY) {
+    // Tracking not configured, skip silently
+    return;
+  }
+
+  try {
+    const response = await fetch(MD_TRACKING_URL, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+        Authorization: `Bearer ${MD_TRACKING_API_KEY}`
+      },
+      body: JSON.stringify({
+        path,
+        source: "turborepo",
+        userAgent,
+        referer,
+        acceptHeader
+      })
+    });
+
+    if (!response.ok) {
+      console.error(
+        "MD tracking failed:",
+        response.status,
+        await response.text()
+      );
+    }
+  } catch (error) {
+    // Fire-and-forget: don't let tracking errors affect the response
+    console.error("MD tracking error:", error);
+  }
+}