diff --git a/server/src/__tests__/idle-admission.test.ts b/server/src/__tests__/idle-admission.test.ts
index 3725230d93..19f30ad08c 100644
--- a/server/src/__tests__/idle-admission.test.ts
+++ b/server/src/__tests__/idle-admission.test.ts
@@ -1,6 +1,7 @@
 import express from "express";
 import request from "supertest";
 import { request as httpRequest } from "node:http";
+import { createServer as createViteServer } from "vite";
 import { afterEach, describe, expect, it } from "vitest";
 import { idleAdmissionMiddleware, trackIdleRequestHandlers } from "../middleware/idle-admission.js";
 import { idleWorkSnapshot, startTaskDrain, stopTaskDrain, readTaskDrain, beginIdleTrackedWork } from "../services/task-admission.js";
@@ -63,6 +64,25 @@ describe("idle admission", () => {
     expect(idleWorkSnapshot().active).toBe(0);
   });
 
+  it("supports real Vite Connect route metadata without losing async work", async () => {
+    const vite = await createViteServer({ configFile: false, appType: "custom",
+      server: { middlewareMode: true, watch: null }, optimizeDeps: { noDiscovery: true, include: [] } });
+    const server = app(), done = deferred();
+    try {
+      server.use(vite.middlewares);
+      server.post("/work", async (_req, res) => { res.sendStatus(202); await done.promise; });
+      expect(() => trackIdleRequestHandlers(server)).not.toThrow();
+      await request(server).post("/work").expect(202);
+      expect(idleWorkSnapshot().active).toBe(1);
+      done.resolve();
+      await new Promise(resolve => setImmediate(resolve));
+      expect(idleWorkSnapshot().active).toBe(0);
+    } finally {
+      done.resolve();
+      await vite.close();
+    }
+  });
+
   it("does not mistake a client disconnect for completed accepted work", async () => {
     const server = app();
     const entered = deferred(), done = deferred(), closed = deferred();
diff --git a/server/src/middleware/idle-admission.ts b/server/src/middleware/idle-admission.ts
index 2016b9ca85..92b1e36aa9 100644
--- a/server/src/middleware/idle-admission.ts
+++ b/server/src/middleware/idle-admission.ts
@@ -60,7 +60,7 @@ export function trackIdleRequestHandlers(app: Application): void {
     for (const layer of stack) {
       if (seen.has(layer)) continue;
       seen.add(layer);
-      if (layer.route) { visit(layer.route.stack, true); continue; }
+      if (layer.route && Array.isArray(layer.route.stack)) { visit(layer.route.stack, true); continue; }
       if (Array.isArray(layer.handle.stack)) { visit(layer.handle.stack); continue; }
       const original = layer.handle;
       if (original === idleAdmissionMiddleware) continue;