diff --git a/packages/cli/src/commands/preview.ts b/packages/cli/src/commands/preview.ts
index 62bedf8338..855c52369c 100644
--- a/packages/cli/src/commands/preview.ts
+++ b/packages/cli/src/commands/preview.ts
@@ -54,6 +54,7 @@ import { runRenderSetupWorker } from "../utils/cancellableProcess.js";
 import { formatLintStartupMessage } from "../utils/lintFormat.js";
 import {
   activeServerOnPort,
+  closeServer,
   findPortAndServe,
   scanActiveServers,
   killActiveServers,
@@ -1743,7 +1744,7 @@ export async function runEmbeddedMode(
         .catch(() => {})
         .finally(() => {
           watcher.close();
-          result.server.close(() => resolveRun());
+          void closeServer(result.server).then(resolveRun);
         });
     };
     // `on`, not `once`: a repeat Ctrl+C/SIGTERM while shutdown is running must
diff --git a/packages/cli/src/server/portUtils.test.ts b/packages/cli/src/server/portUtils.test.ts
index e21a9f6a2d..ac5562367f 100644
--- a/packages/cli/src/server/portUtils.test.ts
+++ b/packages/cli/src/server/portUtils.test.ts
@@ -2,10 +2,11 @@ import { afterEach, describe, expect, it, vi } from "vitest";
 import { createServer, type Server } from "node:net";
 import { spawn } from "node:child_process";
 import { resolve } from "node:path";
-import { createServer as createHttpServer, type Server as HttpServer } from "node:http";
+import { createServer as createHttpServer, get, type Server as HttpServer } from "node:http";
 import {
   PORT_PROBE_HOSTS,
   activeServerOnPort,
+  closeServer,
   detectHyperframesServer,
   findPortAndServe,
   testPortOnAllHosts,
@@ -306,3 +307,25 @@ describe("detectHyperframesServer", () => {
     expect(result).toEqual({ type: "match" });
   });
 });
+
+describe("closeServer", () => {
+  it("closes while a client holds an event stream open", async () => {
+    const server = createHttpServer((_req, res) => {
+      res.writeHead(200, { "content-type": "text/event-stream" });
+      res.write(": open\n\n");
+    });
+    const port = await new Promise<number>((resolve) =>
+      server.listen(0, "127.0.0.1", () =>
+        resolve((server.address() as import("node:net").AddressInfo).port),
+      ),
+    );
+    await new Promise<void>((resolve) =>
+      get(`http://127.0.0.1:${port}/`, (res) => {
+        res.on("error", () => {});
+        resolve();
+      }).on("error", () => {}),
+    );
+    await closeServer(server);
+    expect(server.listening).toBe(false);
+  });
+});
diff --git a/packages/cli/src/server/portUtils.ts b/packages/cli/src/server/portUtils.ts
index c0a1971118..3c13d1967f 100644
--- a/packages/cli/src/server/portUtils.ts
+++ b/packages/cli/src/server/portUtils.ts
@@ -413,6 +413,12 @@ export async function killActiveServers(
   return { killed, unverified };
 }
 
+/** Stops `server` once every open connection is closed too; an open Studio tab holds its event stream for its life. */
+export function closeServer(server: import("@hono/node-server").ServerType): Promise<void> {
+  if ("closeAllConnections" in server) server.closeAllConnections();
+  return new Promise((resolve) => server.close(() => resolve()));
+}
+
 // ── Smart port selection ───────────────────────────────────────────────────
 
 export type FindPortResult =
diff --git a/packages/cli/src/server/studioServer.test.ts b/packages/cli/src/server/studioServer.test.ts
index 1cb82924b3..962eef661d 100644
--- a/packages/cli/src/server/studioServer.test.ts
+++ b/packages/cli/src/server/studioServer.test.ts
@@ -891,6 +891,17 @@ describe("Studio file-change SSE", () => {
     return { projectDir, projectUrl };
   }
 
+  it("leaves no timer behind once the tab disconnects, so a stopping CLI can exit", async () => {
+    server = createStudioServer({ projectDir: tmpProject() });
+    const timeouts = vi.spyOn(globalThis, "setTimeout");
+    const [stream] = await subscribe(1);
+    await stream!.cancel();
+
+    const keepAlive = timeouts.mock.calls.filter(([, ms]) => (ms ?? 0) >= 30_000);
+    timeouts.mockRestore();
+    expect(keepAlive).toEqual([]);
+  });
+
   it("marks a notes write as not affecting the preview, so the tab does not reload", async () => {
     const { projectDir } = await previewedProject();
     const [stream] = await subscribe(1);
diff --git a/packages/cli/src/server/studioServer.ts b/packages/cli/src/server/studioServer.ts
index 52c60eaaa3..91bba7cfa8 100644
--- a/packages/cli/src/server/studioServer.ts
+++ b/packages/cli/src/server/studioServer.ts
@@ -1034,14 +1034,8 @@ export function createStudioServer(options: StudioServerOptions): StudioServer {
         if (shouldWatchProjectFile(changedPath)) listener(changedPath);
       };
       watcher.addListener(wrappedListener);
-      stream.onAbort(() => watcher.removeListener(wrappedListener));
-      try {
-        while (true) {
-          await stream.sleep(30000);
-        }
-      } finally {
-        watcher.removeListener(wrappedListener);
-      }
+      if (!stream.aborted) await new Promise<void>((tabClosed) => stream.onAbort(tabClosed));
+      watcher.removeListener(wrappedListener);
     });
   });