diff --git a/tests/README.md b/tests/README.md
index c14c2e96f..13cb5a5b8 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -707,7 +707,7 @@ desktop GUI, a real `launchctl` or `schtasks` run, or a login/reboot pass.
 | Follow-up turns and conversation resume | Not covered; reopen proves startup, not conversation resume |
 | Claude/Codex interactive smart routing | First-prompt routing is covered by the `managed_fixture` banner journeys and CUJ4. The live subagent-only journeys spawn native children and invoke the installed Smart Router skill to verify routing on -> off -> on within one Claude/Codex session. The scheduled harness-latest workflow repeats CUJ4, routing hooks, skill toggles, and banners with both latest agents. Plugin-refresh survival and native daemon/background dispatch remain deferred. |
 | Full allow/deny tool-permission matrix | Not covered; onboarding/trust uses actual TUI choices |
-| Desktop Codex app, Isaac itself, auto-upgrades | Not covered by command forwarding or pinned-version tests |
+| Desktop Codex app, Isaac itself, auto-upgrades | Not covered by command forwarding or pinned-version tests. Codex desktop's shared-config catalog pointer (repeat configure and a user-owned pointer) is covered by `integration/test_ug_configure_codex_desktop.py`; desktop tracing, GUI, and inference are not |
 | Native macOS/Windows live TUI, managed settings, resize/signals | Windows fresh-install, CLI, local helpers, and the Claude headless gateway journey are advisory; Codex Windows CI is blocked on npm proxy access. Live PTY/TUI, managed settings, and signal behavior still need separate platform implementation and coverage |
 | Other agents | Live scope is Claude Code and Codex, plus a non-blocking OpenCode headless case |
 | OpenCode `--model` / `-m` | Unit/component tests cover raw CLI forwarding, configured model selection, launch arguments, rejection of unknown models before starting the native process, and the existing failure when no default model is available; no dedicated live integration journey |
diff --git a/tests/integration/README.md b/tests/integration/README.md
index 4e188c967..2e7b3af5f 100644
--- a/tests/integration/README.md
+++ b/tests/integration/README.md
@@ -26,6 +26,13 @@ selection, and an unrelated profile. It does not launch Desktop. The
 macOS/Windows GUI, Cowork, model-switching, and browser-authentication work; those GUI and
 virtualization prerequisites are not satisfied by the headless suite.
 
+Codex desktop has managed-fixture coverage in `test_ug_configure_codex_desktop.py`. It
+configures twice beside user-owned `~/.codex/config.toml` settings and checks the stable catalog
+pointer and an unchanged repeat configure with no restart notice; a second case keeps a user-owned
+catalog pointer through configure and revert. Revert of ug's pointer is covered by
+`test_ug_codex_managed_model_discovery.py`. It does not cover desktop tracing (its systemd/launchd
+service needs a user session), the GUI, or inference.
+
 The separate [dedicated-workspace CUJ](../e2e_cuj/AGENTS.md) lives in `tests/e2e_cuj/`
 and runs directly with pytest. It does not use this suite's runner or config fixtures.
 It reuses the session, terminal, file-task, and transcript helpers in `utils/`.
@@ -458,6 +465,7 @@ test_ug_codex_app_server.py             # actual client/server initialize exchan
 test_ug_smart_routing_hooks.py           # live hook contract plus skill-driven subagent toggles
 test_ug_configure_claude_lifecycle.py   # repeat setup, revert, rejected credentials
 test_ug_configure_claude_desktop.py     # native-path Desktop profile lifecycle, no GUI
+test_ug_configure_codex_desktop.py      # stubbed managed Codex desktop catalog pointer, no GUI
 test_ug_configure_claude_workspace_switch.py # real skills MCP cleanup across two workspaces
 test_ug_configure_codex_lifecycle.py    # repeat setup, revert, rejected credentials
 test_ug_claude_managed_model_discovery.py # Claude MPS policy cases (claude_mps.json)
diff --git a/tests/integration/test_ug_configure_codex_desktop.py b/tests/integration/test_ug_configure_codex_desktop.py
new file mode 100644
index 000000000..e628f1ee9
--- /dev/null
+++ b/tests/integration/test_ug_configure_codex_desktop.py
@@ -0,0 +1,75 @@
+"""Black-box lifecycle coverage for the Codex desktop app's shared config and model catalog."""
+
+import hashlib
+import json
+import tomllib
+
+import pytest
+from utils.managed import use_managed_config_fixture
+from utils.terminal import TerminalProcess
+
+pytestmark = [pytest.mark.managed_fixture, pytest.mark.codex]
+
+USER_SETTINGS = "# user-owned Codex settings\n[notice]\nhide_rate_limit_model_nudge = true\n"
+RESTART_NOTICE = "codex app-server daemon restart"
+
+
+def _digest(path) -> str:
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+def test_ug_configure_codex_desktop_repeat_configure(live_session, workspace):
+    """Scenario: configure managed Codex twice beside user-owned settings.
+
+    Expected: the shared `~/.codex/config.toml` that the desktop app reads gains one pointer to
+    ug's stable catalog and keeps the user's settings; a repeat configure rewrites neither file
+    and prints no daemon-restart notice. The catalog's models and a bare `codex app-server`
+    `model/list` are covered by `test_ug_configure_managed_codex`, and revert by
+    `test_case_02_managed_codex_uses_admin_discovery_after_configure`. Desktop tracing, GUI
+    rendering, and inference are not covered.
+    """
+    session = live_session
+    shared_config = session.home / ".codex" / "config.toml"
+    catalog_path = session.home / ".ucode" / "codex-model-catalog.json"
+    # Ordinary pre-existing user settings, not manufactured gateway state.
+    shared_config.parent.mkdir(parents=True)
+    shared_config.write_text(USER_SETTINGS)
+    use_managed_config_fixture(session, "managed_workspace_default")
+    configure_args = ("configure", "--workspace", workspace, "--skip-upgrade")
+
+    first = session.run(*configure_args, timeout=240)
+    assert RESTART_NOTICE in " ".join(first.stderr.split()), first.stderr
+    configured = tomllib.loads(shared_config.read_text())
+    assert configured.pop("model_catalog_json") == str(catalog_path), configured
+    assert configured == tomllib.loads(USER_SETTINGS)
+
+    before = (_digest(shared_config), _digest(catalog_path))
+    second = session.run(*configure_args, timeout=240)
+    assert RESTART_NOTICE not in " ".join(second.stderr.split()), second.stderr
+    assert (_digest(shared_config), _digest(catalog_path)) == before
+
+
+def test_ug_configure_codex_desktop_keeps_user_catalog(live_session, workspace):
+    """Scenario: the user already points the desktop app at their own model catalog.
+
+    Expected: configure warns and leaves the user's pointer and catalog file byte-identical, and
+    revert neither removes the pointer nor deletes the user's file.
+    """
+    session = live_session
+    shared_config = session.home / ".codex" / "config.toml"
+    user_catalog = session.home / "my-catalog.json"
+    # User-owned inputs: a catalog file and the pointer to it. JSON quoting keeps Windows paths
+    # valid TOML.
+    user_catalog.write_text(json.dumps({"models": []}))
+    shared_config.parent.mkdir(parents=True)
+    shared_config.write_text(f"model_catalog_json = {json.dumps(str(user_catalog))}\n")
+    original = (shared_config.read_text(), user_catalog.read_text())
+    use_managed_config_fixture(session, "managed_workspace_default")
+
+    result = session.run("configure", "--workspace", workspace, "--skip-upgrade", timeout=240)
+    assert "custom model catalog" in " ".join(result.stderr.split()), result.stderr
+    assert (shared_config.read_text(), user_catalog.read_text()) == original
+
+    with TerminalProcess(session, "ug", [str(session.binary), "revert"], "desktop-keep") as tty:
+        tty.finish()
+    assert (shared_config.read_text(), user_catalog.read_text()) == original