diff --git a/hermes_cli/cli_model_switch_mixin.py b/hermes_cli/cli_model_switch_mixin.py
index 9d6a12a62f..6eb134bd6f 100644
--- a/hermes_cli/cli_model_switch_mixin.py
+++ b/hermes_cli/cli_model_switch_mixin.py
@@ -356,9 +356,10 @@ class CLIModelSwitchMixin:
 
         # 2. Replace untouched default with a Codex model
         if self._model_is_default:
-            fallback_model = "gpt-5.3-codex"
+            from hermes_cli.codex_models import DEFAULT_CODEX_MODELS, get_codex_model_ids
+
+            fallback_model = DEFAULT_CODEX_MODELS[0]
             try:
-                from hermes_cli.codex_models import get_codex_model_ids
                 available = get_codex_model_ids(access_token=self.api_key if self.api_key else None)
                 if available:
                     fallback_model = available[0]
diff --git a/run_agent.py b/run_agent.py
index 73208e3227..6165032eff 100644
--- a/run_agent.py
+++ b/run_agent.py
@@ -627,7 +627,7 @@ class AIAgent(
             "on chatgpt.com/backend-api/codex (no stream events, no error). "
             "This is a known backend-side pattern that has affected ChatGPT "
             "Plus accounts intermittently. "
-            "Workaround: try `gpt-5.4` on the same OAuth profile, or `gpt-5.3-codex`, "
+            "Workaround: try `gpt-5.4` on the same OAuth profile, "
             "or switch to a different model/provider in your fallback chain. "
             "Some ChatGPT Codex accounts do not support `gpt-5.4-codex`. "
             "See hermes-agent#21444 for symptom history."
diff --git a/tests/agent/test_codex_silent_hang_hint.py b/tests/agent/test_codex_silent_hang_hint.py
index 873ab5a8ee..447b0d11ba 100644
--- a/tests/agent/test_codex_silent_hang_hint.py
+++ b/tests/agent/test_codex_silent_hang_hint.py
@@ -4,7 +4,7 @@ The helper substitutes an actionable hint into the stale-call timeout
 warning when the request matches a known Codex silent-reject pattern
 (gpt-5.5 family on the ChatGPT Codex backend).  See issue #21444 for
 symptom history. The recommended workaround for ChatGPT Codex OAuth
-accounts is `gpt-5.4` / `gpt-5.3-codex`, not `gpt-5.4-codex`.
+accounts is `gpt-5.4`, not `gpt-5.4-codex` (gpt-5.3-codex is retired, #52492).
 """
 
 from __future__ import annotations
@@ -45,7 +45,7 @@ def test_hint_fires_for_bare_gpt_5_5_on_codex(tmp_path):
     hint = agent._codex_silent_hang_hint(model="gpt-5.5")
     assert hint is not None
     assert "gpt-5.4" in hint
-    assert "gpt-5.3-codex" in hint
+    assert "gpt-5.3-codex" not in hint
     assert "gpt-5.4-codex" in hint
     assert "fallback chain" in hint
 
diff --git a/tests/agent/test_codex_ttfb_watchdog.py b/tests/agent/test_codex_ttfb_watchdog.py
index 1609a0ff4d..4fbbe6564c 100644
--- a/tests/agent/test_codex_ttfb_watchdog.py
+++ b/tests/agent/test_codex_ttfb_watchdog.py
@@ -140,11 +140,11 @@ def test_ttfb_includes_silent_hang_hint_for_gpt_5_5(tmp_path, monkeypatch):
             h.interruptible_api_call(agent, {"model": "gpt-5.5", "input": "hi"})
         message = str(excinfo.value)
         assert "gpt-5.4" in message
-        assert "gpt-5.3-codex" in message
+        assert "gpt-5.3-codex" not in message
         assert "gpt-5.4-codex" in message
         assert "codex_ttfb_kill" in closes
         assert statuses, "expected a user-facing watchdog status"
-        assert any("gpt-5.4" in s and "gpt-5.3-codex" in s for s in statuses)
+        assert any("gpt-5.4" in s and "gpt-5.3-codex" not in s for s in statuses)
     finally:
         stop["flag"] = True
 
diff --git a/tests/hermes_cli/test_codex_models.py b/tests/hermes_cli/test_codex_models.py
index 78a057711f..66b7657726 100644
--- a/tests/hermes_cli/test_codex_models.py
+++ b/tests/hermes_cli/test_codex_models.py
@@ -66,6 +66,21 @@ def test_picker_never_synthesizes_900k_for_pro_or_unknown_slugs():
 
 
 
+def test_retired_gpt_5_3_codex_is_not_offered_offline():
+    """The ChatGPT Codex backend retired ``gpt-5.3-codex`` (HTTP 400 "not supported when using
+    Codex with a ChatGPT account", #52492). Neither the curated offline fallback nor any
+    forward-compat template may surface it — only live discovery may, if the backend re-enables it.
+    Same precedent as the gpt-5.2-codex / gpt-5.1-codex-* removal (e8955f222ce)."""
+    from hermes_cli.codex_models import _FORWARD_COMPAT_TEMPLATE_MODELS, DEFAULT_CODEX_MODELS
+
+    assert "gpt-5.3-codex" not in DEFAULT_CODEX_MODELS
+    for newer, templates in _FORWARD_COMPAT_TEMPLATE_MODELS:
+        assert newer != "gpt-5.3-codex"
+        assert "gpt-5.3-codex" not in templates
+    # Spark is still a real Codex-OAuth slug and must keep surfacing via a live template.
+    assert "gpt-5.3-codex-spark" in DEFAULT_CODEX_MODELS
+
+
 def test_setup_wizard_codex_import_resolves():
     """Regression test for #712: setup.py must import the correct function name."""
     # This mirrors the exact import used in hermes_cli/setup.py line 873.
@@ -170,7 +185,7 @@ def test_model_command_prompts_to_reuse_or_reauthenticate_codex_session(monkeypa
     monkeypatch.setattr("hermes_cli.auth._login_openai_codex", _fake_login)
     monkeypatch.setattr(
         "hermes_cli.codex_models.get_codex_model_ids",
-        lambda access_token=None: ["gpt-5.4", "gpt-5.3-codex"],
+        lambda access_token=None: ["gpt-5.4", "gpt-5.5"],
     )
     monkeypatch.setattr(
         "hermes_cli.auth._prompt_model_selection",
@@ -263,12 +278,12 @@ class TestNormalizeModelForProvider:
         assert cli._model_is_default is True
         with patch(
             "hermes_cli.codex_models.get_codex_model_ids",
-            return_value=["gpt-5.3-codex", "gpt-5.4"],
+            return_value=["gpt-5.5", "gpt-5.4"],
         ):
             changed = cli._normalize_model_for_provider("openai-codex")
         assert changed is True
         # Uses first from available list
-        assert cli.model == "gpt-5.3-codex"
+        assert cli.model == "gpt-5.5"
 
 
 def test_catalog_requests_use_ungated_client_version(monkeypatch):
diff --git a/website/docs/user-guide/configuration.md b/website/docs/user-guide/configuration.md
index 9f9f22ad30..5519255cf9 100644
--- a/website/docs/user-guide/configuration.md
+++ b/website/docs/user-guide/configuration.md
@@ -1676,7 +1676,7 @@ These options apply to **auxiliary task configs** (`auxiliary:`, `compression:`)
 | `"auto"` | Best available (default). Vision tries OpenRouter → Nous → Codex. | — |
 | `"openrouter"` | Force OpenRouter — routes to any model (Gemini, GPT-4o, Claude, etc.) | `OPENROUTER_API_KEY` |
 | `"nous"` | Force Nous Portal | `hermes auth` |
-| `"codex"` | Force Codex OAuth (ChatGPT account). Supports vision (gpt-5.3-codex). | `hermes model` → ChatGPT or Codex Subscription |
+| `"codex"` | Force Codex OAuth (ChatGPT account). Set `model` explicitly (e.g. `gpt-5.4`). | `hermes model` → ChatGPT or Codex Subscription |
 | `"minimax-oauth"` | Force MiniMax OAuth (browser login, no API key). Uses MiniMax-M2.7-highspeed for auxiliary tasks. | `hermes model` → MiniMax (OAuth) |
 | `"xai-oauth"` | Force xAI Grok OAuth (browser login for SuperGrok or X Premium+ subscribers, no API key). Same OAuth token covers chat, TTS, image, video, and transcription. | `hermes model` → xAI Grok OAuth (SuperGrok / Premium+) |
 | `"main"` | Use your active custom/main endpoint. This can come from `OPENAI_BASE_URL` + `OPENAI_API_KEY` or from a custom endpoint saved via `hermes model` / `config.yaml`. Works with OpenAI, local models, or any OpenAI-compatible API. **Auxiliary tasks only — not valid for `model.provider`.** | Custom endpoint credentials + base URL |
@@ -1730,7 +1730,7 @@ auxiliary:
 auxiliary:
   vision:
     provider: "codex"     # uses your ChatGPT OAuth token
-    # model defaults to gpt-5.3-codex (supports vision)
+    model: "gpt-5.4"      # no implicit default on the Codex route
 ```
 
 **Using MiniMax OAuth** (browser login, no API key needed):
diff --git a/website/docs/user-guide/features/fallback-providers.md b/website/docs/user-guide/features/fallback-providers.md
index fcb033ca10..464cdf65b1 100644
--- a/website/docs/user-guide/features/fallback-providers.md
+++ b/website/docs/user-guide/features/fallback-providers.md
@@ -179,7 +179,7 @@ fallback_providers:
 ```yaml
 fallback_providers:
   - provider: openai-codex
-    model: gpt-5.3-codex
+    model: gpt-5.4
 ```
 
 ### Where Fallback Works
diff --git a/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/configuration.md b/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/configuration.md
index 9e86946da6..6dc7ebb343 100644
--- a/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/configuration.md
+++ b/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/configuration.md
@@ -1000,7 +1000,7 @@ AUXILIARY_VISION_MODEL=openai/gpt-4o
 | `"auto"` | 最佳可用（默认）。Vision 尝试 OpenRouter → Nous → Codex。 | — |
 | `"openrouter"` | 强制 OpenRouter —— 路由到任何模型（Gemini、GPT-4o、Claude 等） | `OPENROUTER_API_KEY` |
 | `"nous"` | 强制 Nous Portal | `hermes auth` |
-| `"codex"` | 强制 Codex OAuth（ChatGPT 账户）。支持视觉（gpt-5.3-codex）。 | `hermes model` → ChatGPT or Codex Subscription |
+| `"codex"` | 强制 Codex OAuth（ChatGPT 账户）。请显式设置 `model`（例如 `gpt-5.4`）。 | `hermes model` → ChatGPT or Codex Subscription |
 | `"minimax-oauth"` | 强制 MiniMax OAuth（浏览器登录，无需 API 密钥）。辅助任务使用 MiniMax-M2.7-highspeed。 | `hermes model` → MiniMax (OAuth) |
 | `"xai-oauth"` | 强制 xAI Grok OAuth（SuperGrok 或 X Premium+ 订阅者的浏览器登录，无需 API 密钥）。相同的 OAuth token 涵盖聊天、TTS、图像、视频和转录。 | `hermes model` → xAI Grok OAuth (SuperGrok / Premium+) |
 | `"main"` | 使用您的活跃自定义/主端点。可以来自 `OPENAI_BASE_URL` + `OPENAI_API_KEY` 或通过 `hermes model` / `config.yaml` 保存的自定义端点。适用于 OpenAI、本地模型或任何 OpenAI 兼容 API。**仅限辅助任务 —— 对 `model.provider` 无效。** | 自定义端点凭据 + 基础 URL |
@@ -1054,7 +1054,7 @@ auxiliary:
 auxiliary:
   vision:
     provider: "codex"     # 使用您的 ChatGPT OAuth token
-    # 模型默认为 gpt-5.3-codex（支持视觉）
+    model: "gpt-5.4"      # Codex 路径没有隐式默认模型
 ```
 
 **使用 MiniMax OAuth**（浏览器登录，无需 API 密钥）：
diff --git a/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/features/fallback-providers.md b/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/features/fallback-providers.md
index 183d069c23..e679e33db7 100644
--- a/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/features/fallback-providers.md
+++ b/website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/features/fallback-providers.md
@@ -158,7 +158,7 @@ fallback_model:
 ```yaml
 fallback_model:
   provider: openai-codex
-  model: gpt-5.3-codex
+  model: gpt-5.4
 ```
 
 ### 备用适用范围