diff --git a/src/core/worker-pool.ts b/src/core/worker-pool.ts
index ac3fc6ea8..0ab1ad21a 100644
--- a/src/core/worker-pool.ts
+++ b/src/core/worker-pool.ts
@@ -10750,7 +10750,21 @@ function setupWorkerHandlers(
           logger.warn(`[${t}] Ignored restart_result from stale worker generation`);
           break;
         }
-        restartCoordinator.resolve(ds.session.sessionId, msg.attemptId, msg.status);
+        const restartSettled = restartCoordinator.resolve(
+          ds.session.sessionId,
+          msg.attemptId,
+          msg.status,
+        );
+        // requestSessionRestart() fences the live generation by clearing
+        // workerReady before asking the worker to respawn its CLI in place. An
+        // in-worker respawn does not emit the process-level `ready` message
+        // again, so the matching successful receipt is the authoritative edge
+        // that must release that fence. Without this assignment the terminal
+        // can be prompt-ready/idle while relay and fork remain permanently
+        // blocked as `worker_busy`.
+        if (restartSettled && msg.status === 'succeeded') {
+          ds.workerReady = true;
+        }
         break;
       }
 
diff --git a/test/restart-worker-ready-lifecycle.test.ts b/test/restart-worker-ready-lifecycle.test.ts
new file mode 100644
index 000000000..6bd7b2d13
--- /dev/null
+++ b/test/restart-worker-ready-lifecycle.test.ts
@@ -0,0 +1,36 @@
+import { readFileSync } from 'node:fs';
+import { describe, expect, it } from 'vitest';
+
+const workerPoolSource = readFileSync(
+  new URL('../src/core/worker-pool.ts', import.meta.url),
+  'utf8',
+);
+
+describe('in-worker restart lifecycle fence', () => {
+  it('releases workerReady only after the current restart succeeds', () => {
+    const start = workerPoolSource.indexOf("case 'restart_result':");
+    const end = workerPoolSource.indexOf("case 'cli_session_id':", start);
+    expect(start).toBeGreaterThanOrEqual(0);
+    expect(end).toBeGreaterThan(start);
+
+    const branch = workerPoolSource.slice(start, end);
+    const staleWorkerGuard = branch.indexOf('if (ds.worker !== worker)');
+    const resolve = branch.indexOf('restartCoordinator.resolve(');
+    const successGuard = branch.indexOf("restartSettled && msg.status === 'succeeded'");
+    const releaseFence = branch.indexOf('ds.workerReady = true;');
+
+    expect(staleWorkerGuard).toBeGreaterThanOrEqual(0);
+    expect(resolve).toBeGreaterThan(staleWorkerGuard);
+    expect(successGuard).toBeGreaterThan(resolve);
+    expect(releaseFence).toBeGreaterThan(successGuard);
+  });
+
+  it('keeps failed or stale restart receipts from releasing workerReady', () => {
+    const start = workerPoolSource.indexOf("case 'restart_result':");
+    const end = workerPoolSource.indexOf("case 'cli_session_id':", start);
+    const branch = workerPoolSource.slice(start, end);
+
+    expect(branch.match(/ds\.workerReady = true;/g)).toHaveLength(1);
+    expect(branch).toContain("if (restartSettled && msg.status === 'succeeded')");
+  });
+});