diff --git a/middleware.ts b/middleware.ts
index 990ac9f..76c1499 100644
--- a/middleware.ts
+++ b/middleware.ts
@@ -19,6 +19,10 @@
  *
  * Health/metrics are exempt (they are also outside the matcher below, but the
  * exemption is kept explicit for robustness).
+ *
+ * FIX (2026-08-31): matcher now covers BOTH /api/0pt (exact) and /api/0pt/:path*
+ * to close the gap where a bare GET /api/0pt (no trailing path) was routed around
+ * the middleware on Vercel's Edge runtime.
  */
 
 import { NextResponse, type NextRequest } from 'next/server';
@@ -30,7 +34,7 @@ assertAuthConfigSafe();
 // Only guard the 0pt capability surface. The matcher keeps this middleware off
 // the UI, auth, and payment routes entirely.
 export const config = {
-  matcher: ['/api/0pt/:path*'],
+  matcher: ['/api/0pt', '/api/0pt/:path*'],
 };
 
 const EXEMPT_PATTERNS: RegExp[] = [
@@ -39,12 +43,26 @@ const EXEMPT_PATTERNS: RegExp[] = [
   /^\/api\/admin\/metrics(\/|$)/,
 ];
 
+// Module-level diagnostics counter — first 5 auth requests in a process lifetime
+// log their outcome so the production auth gap (S1) can be traced to root cause.
+let _authDiagCount = 0;
+
 export async function middleware(req: NextRequest): Promise<NextResponse> {
   const path = req.nextUrl.pathname;
   if (EXEMPT_PATTERNS.some((re) => re.test(path))) {
     return NextResponse.next();
   }
 
+  if (_authDiagCount < 5) {
+    _authDiagCount += 1;
+    const hasAuth = !!req.headers.get('authorization');
+    console.log(
+      `[0pt-auth] middleware path=${path} auth_header=${hasAuth} ` +
+      `auth_enforce=${process.env.AUTH_ENFORCE ?? 'unset'} ` +
+      `node_env=${process.env.NODE_ENV ?? 'unset'} request#${_authDiagCount}`,
+    );
+  }
+
   const decision = await resolveAuthContext(req.headers);
 
   if (!decision.ok) {