diff --git a/extensions/codex/src/app-server/shared-client.test.ts b/extensions/codex/src/app-server/shared-client.test.ts
index f9a3255eddb7..c0f7d03a1945 100644
--- a/extensions/codex/src/app-server/shared-client.test.ts
+++ b/extensions/codex/src/app-server/shared-client.test.ts
@@ -863,6 +863,34 @@ describe("shared Codex app-server client", () => {
     });
   });
 
+  it.each(["config", "env"] as const)(
+    "rejects a stale %s-selected standard desktop client",
+    async (commandSource) => {
+      const generationX = { epoch: 1, fingerprint: "desktop-x" };
+      mocks.desktopGeneration = generationX;
+      const harness = createClientHarness();
+      vi.spyOn(CodexAppServerClient, "start").mockReturnValueOnce(harness.client);
+      const startOptions: CodexAppServerStartOptions = {
+        transport: "stdio",
+        homeScope: "agent",
+        command: "/Applications/ChatGPT.app/Contents/Resources/codex",
+        commandSource,
+        args: ["app-server"],
+        headers: {},
+      };
+
+      const clientPromise = createIsolatedCodexAppServerClient({ startOptions });
+      await sendInitializeResult(harness, "openclaw/0.148.0 (macOS; test)");
+      const client = await clientPromise;
+
+      mocks.desktopGeneration = { epoch: 2, fingerprint: "desktop-y" };
+      expect(() =>
+        assertCodexAppServerClientStartSelectionCurrent({ client, startOptions }),
+      ).toThrow("managed executable selection changed during startup");
+      client.close();
+    },
+  );
+
   it.each(["abort", "timeout"] as const)(
     "holds the native config fence through process exit after a post-write %s",
     async (mode) => {
diff --git a/extensions/codex/src/app-server/shared-client.ts b/extensions/codex/src/app-server/shared-client.ts
index dd867193ca65..60251683bac8 100644
--- a/extensions/codex/src/app-server/shared-client.ts
+++ b/extensions/codex/src/app-server/shared-client.ts
@@ -238,13 +238,13 @@ export function assertCodexAppServerClientStartSelectionCurrent(params: {
   if (!metadata) {
     return;
   }
+  if (metadata.desktopGeneration && !isCodexDesktopGenerationCurrent(metadata.desktopGeneration)) {
+    throw new CodexAppServerStartSelectionChangedError();
+  }
   const requestedStartOptions = params.startOptions ?? metadata.requestedStartOptions;
   if (requestedStartOptions.commandSource !== "managed") {
     return;
   }
-  if (metadata.desktopGeneration && !isCodexDesktopGenerationCurrent(metadata.desktopGeneration)) {
-    throw new CodexAppServerStartSelectionChangedError();
-  }
   const current = resolveCodexAppServerStartOptionsForAgent({
     startOptions: requestedStartOptions,
     agentDir: params.agentDir ?? metadata.agentDir,