diff --git a/scripts/benchmark-live.mjs b/scripts/benchmark-live.mjs
index 214540849..12a16a4d8 100644
--- a/scripts/benchmark-live.mjs
+++ b/scripts/benchmark-live.mjs
@@ -557,34 +557,39 @@ async function waitForReset(page) {
 }
 
 async function installBrowserTimingProbe(page) {
-  await page.evaluate(() => {
-    const state = { iteration: 0, goAt: null, generateAt: null };
-    window.__IMPECCABLE_LIVE_BENCH_TIMING__ = state;
-    const root = window.__IMPECCABLE_LIVE_CHROME_CORE__?.root?.()
-      || window.__IMPECCABLE_LIVE_UI_ROOT__
-      || document;
-    root.addEventListener('click', (event) => {
-      const button = event.composedPath().find((node) =>
-        node?.getAttribute?.('aria-label') === 'Generate variants'
-      );
-      if (button) state.goAt = performance.now();
-    }, true);
+  await page.addInitScript(installBrowserTimingProbeInPage);
+  await page.evaluate(installBrowserTimingProbeInPage);
+}
 
-    const originalFetch = window.fetch.bind(window);
-    window.fetch = (input, init) => {
-      try {
-        const url = typeof input === 'string' ? input : input?.url;
-        if (String(url || '').endsWith('/events') && init?.method === 'POST') {
-          const payload = typeof init.body === 'string' ? JSON.parse(init.body) : null;
-          if (payload?.type === 'generate') state.generateAt = performance.now();
-        }
-      } catch { /* measurement must never affect Live */ }
-      return originalFetch(input, init);
-    };
-  });
+function installBrowserTimingProbeInPage() {
+  if (window.__IMPECCABLE_LIVE_BENCH_TIMING__?.installed === true) return;
+  const state = { iteration: 0, goAt: null, generateAt: null, installed: true };
+  window.__IMPECCABLE_LIVE_BENCH_TIMING__ = state;
+  const root = window.__IMPECCABLE_LIVE_CHROME_CORE__?.root?.()
+    || window.__IMPECCABLE_LIVE_UI_ROOT__
+    || document;
+  root.addEventListener('click', (event) => {
+    const button = event.composedPath().find((node) =>
+      node?.getAttribute?.('aria-label') === 'Generate variants'
+    );
+    if (button) state.goAt = performance.now();
+  }, true);
+
+  const originalFetch = window.fetch.bind(window);
+  window.fetch = (input, init) => {
+    try {
+      const url = typeof input === 'string' ? input : input?.url;
+      if (String(url || '').endsWith('/events') && init?.method === 'POST') {
+        const payload = typeof init.body === 'string' ? JSON.parse(init.body) : null;
+        if (payload?.type === 'generate') state.generateAt = performance.now();
+      }
+    } catch { /* measurement must never affect Live */ }
+    return originalFetch(input, init);
+  };
 }
 
 async function resetBrowserTimingProbe(page, iteration) {
+  await page.evaluate(installBrowserTimingProbeInPage);
   await page.evaluate((nextIteration) => {
     const state = window.__IMPECCABLE_LIVE_BENCH_TIMING__;
     if (!state) return;
diff --git a/skill/scripts/live/codex-app-server-client.mjs b/skill/scripts/live/codex-app-server-client.mjs
index a75f7ca70..7fc95a9f3 100644
--- a/skill/scripts/live/codex-app-server-client.mjs
+++ b/skill/scripts/live/codex-app-server-client.mjs
@@ -453,6 +453,14 @@ export class CodexAppServerClient {
       await completionPromise;
       await Promise.all(agentMessageCallbacks);
       const completedAt = completed?.receivedAt ?? this.clock();
+      const status = completed?.params?.turn?.status || result.turn?.status || null;
+      if (status !== 'completed') {
+        const interrupted = status === 'interrupted' || status === 'cancelled' || status === 'canceled';
+        throw new CodexAppServerError(`turn ${turnId} completed with status ${status || 'unknown'}`, {
+          code: interrupted ? 'TURN_INTERRUPTED' : 'TURN_FAILED',
+          data: completed?.params?.turn || result.turn || null,
+        });
+      }
       return {
         threadId,
         turnId,
@@ -461,7 +469,7 @@ export class CodexAppServerClient {
         started,
         completed,
         tokenUsage,
-        status: completed?.params?.turn?.status || result.turn?.status || null,
+        status,
         agentMessages,
         message: agentMessages.at(-1) || null,
         requestedAt,
diff --git a/tests/live-codex-app-server-client.test.mjs b/tests/live-codex-app-server-client.test.mjs
index d0547ddc5..f89a35612 100644
--- a/tests/live-codex-app-server-client.test.mjs
+++ b/tests/live-codex-app-server-client.test.mjs
@@ -337,6 +337,33 @@ describe('dedicated Codex worker threads', () => {
     await client.close();
   });
 
+  it('rejects failed turn completions instead of treating them as usable output', async () => {
+    const { client } = await connectClient((message, process) => {
+      if (message.method === 'thread/start') {
+        process.respond(message, { thread: { id: 'worker' } });
+      }
+      if (message.method === 'turn/start') {
+        process.respond(message, { turn: { id: 'turn-failed', status: 'inProgress' } });
+        queueMicrotask(() => {
+          process.send({
+            method: 'turn/completed',
+            params: {
+              threadId: 'worker',
+              turn: { id: 'turn-failed', status: 'failed', error: { message: 'model unavailable' } },
+            },
+          });
+        });
+      }
+    });
+    await client.startDedicatedThread({ serviceName: 'impeccable_live_worker' });
+
+    await assert.rejects(
+      client.startTurn({ threadId: 'worker', input: 'work' }),
+      (error) => error.code === 'TURN_FAILED' && /status failed/.test(error.message),
+    );
+    await client.close();
+  });
+
   it('interrupts, unsubscribes, archives, and cleanly closes', async () => {
     const methods = [];
     const { client, child } = await connectClient((message, process) => {