diff --git a/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.test.ts b/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.test.ts
index 884e953a495d6..76c10382b3cb8 100644
--- a/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.test.ts
+++ b/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.test.ts
@@ -1146,6 +1146,7 @@ describe("CodexAdapterV2 session initialize", () => {
             runtimePolicy: CODEX_TEST_RUNTIME_POLICY,
           }),
         initializeRequests: () => initializeRequests,
+        events: runtime.events,
       };
     });
 
@@ -1293,6 +1294,89 @@ describe("CodexAdapterV2 session initialize", () => {
     ),
   );
 
+  it.effect("fails the open when initialize never answers during open", () =>
+    Effect.gen(function* () {
+      const initializeAwaitingResponse = yield* Deferred.make<void>();
+      const opened = yield* openReplaySession(
+        makeCodexReplayTranscript({
+          scenario: "initialize-hung-open",
+          entries: replayPreamble("initialize-hung-open").slice(0, 2),
+        }),
+        (entry) =>
+          entry.label === "initialize"
+            ? Deferred.succeed(initializeAwaitingResponse, undefined).pipe(
+                Effect.andThen(Effect.never),
+              )
+            : Effect.void,
+        () => Effect.die("initialize never answers"),
+      ).pipe(Effect.flip, Effect.forkChild({ startImmediately: true }));
+      yield* Deferred.await(initializeAwaitingResponse);
+      yield* TestClock.adjust("30 seconds");
+
+      // The session manager discards a session whose open fails.
+      assert.instanceOf(yield* Fiber.join(opened), ProviderAdapter.ProviderAdapterOpenSessionError);
+    }).pipe(
+      Effect.scoped,
+      Effect.provide(
+        Layer.mergeAll(
+          IdAllocator.layer,
+          McpProviderSessions.layer,
+          NodeServices.layer,
+          NodeCrypto.layer,
+        ),
+      ),
+    ),
+  );
+
+  it.effect("retires the shared session when initialize never answers", () =>
+    Effect.gen(function* () {
+      const initializeAwaitingResponse = yield* Deferred.make<void>();
+      const session = yield* openReplaySession(
+        makeCodexReplayTranscript({
+          scenario: "initialize-hung",
+          entries: replayPreamble("initialize-hung").slice(0, 2),
+        }),
+        (entry) =>
+          entry.label === "initialize"
+            ? Deferred.succeed(initializeAwaitingResponse, undefined).pipe(
+                Effect.andThen(Effect.never),
+              )
+            : Effect.void,
+      );
+      const eventsExit = yield* Stream.runDrain(session.events).pipe(
+        Effect.exit,
+        Effect.forkChild({ startImmediately: true }),
+      );
+
+      const ensured = yield* session
+        .ensureThread("thread-initialize-hung")
+        .pipe(Effect.flip, Effect.forkChild({ startImmediately: true }));
+      yield* Deferred.await(initializeAwaitingResponse);
+      const waiting = yield* session
+        .ensureThread("thread-initialize-hung-waiting")
+        .pipe(Effect.flip, Effect.forkChild({ startImmediately: true }));
+      yield* TestClock.adjust("30 seconds");
+
+      assert.equal((yield* Fiber.join(ensured))._tag, "ProviderAdapterEnsureThreadError");
+      // A waiter fails at once instead of re-sending initialize to the hung app-server.
+      assert.equal((yield* Fiber.join(waiting))._tag, "ProviderAdapterEnsureThreadError");
+      assert.equal(session.initializeRequests(), 1);
+      // The session manager retires a session whose event stream fails.
+      const exit = yield* Fiber.join(eventsExit);
+      assert.isTrue(Exit.isFailure(exit));
+    }).pipe(
+      Effect.scoped,
+      Effect.provide(
+        Layer.mergeAll(
+          IdAllocator.layer,
+          McpProviderSessions.layer,
+          NodeServices.layer,
+          NodeCrypto.layer,
+        ),
+      ),
+    ),
+  );
+
   it.effect("completes the handshake after a caller is interrupted mid-initialize", () =>
     Effect.gen(function* () {
       const initializeAwaitingResponse = yield* Deferred.make<void>();
diff --git a/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts b/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts
index 7de690c5e47d0..f7d3b49a687e5 100644
--- a/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts
+++ b/apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.ts
@@ -245,6 +245,8 @@ const decodeCodexBackgroundTerminalTerminateResponse = Schema.decodeUnknownEffec
 const decodeCodexBackgroundTerminalsListResponse = Schema.decodeUnknownEffect(
   CodexBackgroundTerminalsListResponse,
 );
+// Initialize normally answers in under a second; leave room for a slow first launch.
+const CODEX_INITIALIZE_TIMEOUT = "30 seconds";
 const CodexThreadSampleResponse = Schema.Struct({ text: Schema.NullOr(Schema.String) });
 const decodeCodexThreadSampleResponse = Schema.decodeUnknownEffect(CodexThreadSampleResponse);
 export const CODEX_PROMPT_SUGGESTION_PROMPT =
@@ -1929,7 +1931,15 @@ export const makeCodexAdapterV2 = Effect.fn("makeCodexAdapterV2")(function* (
             }),
           ),
         );
+        const events = yield* Queue.unbounded<
+          ProviderAdapter.ProviderAdapterV2Event,
+          ProviderAdapter.ProviderAdapterEventStreamError
+        >();
         const initialized = yield* Ref.make(false);
+        // After a timeout the session is retiring; waiters must not re-send to the hung app-server.
+        const initializeTimeout = yield* Ref.make<
+          ProviderAdapter.ProviderAdapterEventStreamError | undefined
+        >(undefined);
         // Codex rejects a second initialize on the shared app-server.
         const initializePermit = yield* Semaphore.make(1);
         const ensureInitialized = initializePermit.withPermit(
@@ -1938,6 +1948,8 @@ export const makeCodexAdapterV2 = Effect.fn("makeCodexAdapterV2")(function* (
             if (alreadyInitialized) {
               return;
             }
+            const timedOut = yield* Ref.get(initializeTimeout);
+            if (timedOut !== undefined) return yield* timedOut;
 
             const userAgent = yield* client
               .request("initialize", {
@@ -1953,6 +1965,23 @@ export const makeCodexAdapterV2 = Effect.fn("makeCodexAdapterV2")(function* (
                       ? Effect.succeed(null)
                       : Effect.fail(error),
                 }),
+                // A hung app-server never answers, and every thread on this shared
+                // session waits behind the permit. Failing the event stream retires
+                // the session, so the next turn spawns a fresh app-server.
+                Effect.timeoutOrElse({
+                  duration: CODEX_INITIALIZE_TIMEOUT,
+                  orElse: () => {
+                    const error = new ProviderAdapter.ProviderAdapterEventStreamError({
+                      driver: CODEX_PROVIDER,
+                      providerSessionId: input.providerSessionId,
+                      cause: `Codex app-server did not answer initialize within ${CODEX_INITIALIZE_TIMEOUT}.`,
+                    });
+                    return Ref.set(initializeTimeout, error).pipe(
+                      Effect.andThen(Queue.fail(events, error)),
+                      Effect.andThen(Effect.fail(error)),
+                    );
+                  },
+                }),
               );
             const version = userAgent && /\/(\S+)/u.exec(userAgent)?.[1];
             const advisory =
@@ -1982,10 +2011,6 @@ export const makeCodexAdapterV2 = Effect.fn("makeCodexAdapterV2")(function* (
           model: input.modelSelection.model,
           now,
         });
-        const events = yield* Queue.unbounded<
-          ProviderAdapter.ProviderAdapterV2Event,
-          ProviderAdapter.ProviderAdapterEventStreamError
-        >();
         // Drain final notifications before the session manager retires the dead process.
         // Queue.fail lets readers take items already buffered before they see the failure.
         yield* client.awaitTermination.pipe(