diff --git a/apps/codex-plus-manager/src/App.tsx b/apps/codex-plus-manager/src/App.tsx
index bc7bfb264..d29fd37e8 100644
--- a/apps/codex-plus-manager/src/App.tsx
+++ b/apps/codex-plus-manager/src/App.tsx
@@ -3522,7 +3522,7 @@ function EnhanceScreen({
               <FeatureToggle title={t("切换对话保留位置")} detail={t("切换 thread 时恢复上一次浏览位置。")} checked={form.codexAppThreadScrollRestore} disabled={!masterEnabled} onChange={(value) => setEnhanceFlag("codexAppThreadScrollRestore", value)} />
             </FeatureGroup>
             <FeatureGroup title="Stepwise" detail={t("基于当前对话生成下一步建议，使用独立 API 配置。")}>
-              <FeatureToggle title="Stepwise" detail={t("在 Codex 页面显示可拖动的后续建议浮层；建议由单独配置的 Stepwise API 生成。")} checked={form.codexAppStepwiseEnabled} disabled={!masterEnabled} onChange={(value) => setEnhanceFlag("codexAppStepwiseEnabled", value)} />
+              <FeatureToggle title="Stepwise" detail={t("在 Codex 页面显示可拖动的后续建议浮层；建议由单独配置的 Stepwise API 生成。启停后需重启 Codex++ 生效。")} checked={form.codexAppStepwiseEnabled} disabled={!masterEnabled} onChange={(value) => setEnhanceFlag("codexAppStepwiseEnabled", value)} />
               <FeatureToggle title={t("Stepwise 直接发送")} detail={t("点击建议后自动发送；关闭时只填入输入框。")} checked={form.codexAppStepwiseDirectSend} disabled={!masterEnabled || !form.codexAppStepwiseEnabled} onChange={(value) => setEnhanceFlag("codexAppStepwiseDirectSend", value)} />
             </FeatureGroup>
             <FeatureGroup title={t("界面与启动")} detail={t("控制语言、启动速度和 Codex 原生界面调整。")}>
diff --git a/apps/codex-plus-manager/src/i18n-en.ts b/apps/codex-plus-manager/src/i18n-en.ts
index f58b1f382..ab9514f22 100644
--- a/apps/codex-plus-manager/src/i18n-en.ts
+++ b/apps/codex-plus-manager/src/i18n-en.ts
@@ -374,8 +374,8 @@ export const EN_PLAIN: Record<string, string> = {
   "图片覆盖层": "Image overlay",
   "在会话列表悬停显示删除按钮，并支持撤销。": "Show a delete button on hover in the session list, with undo support.",
   "在会话列表显示导出按钮，导出带时间戳的 Markdown。": "Show an export button in the session list to export timestamped Markdown.",
-  "在 Codex 页面显示可拖动的后续建议浮层；建议由单独配置的 Stepwise API 生成。":
-    "Shows a draggable follow-up suggestion overlay in the Codex page. Suggestions are generated by a separate Stepwise API.",
+  "在 Codex 页面显示可拖动的后续建议浮层；建议由单独配置的 Stepwise API 生成。启停后需重启 Codex++ 生效。":
+    "Shows a draggable follow-up suggestion overlay in the Codex page. Suggestions are generated by a separate Stepwise API. Restart Codex++ after changing this setting.",
   "在侧边栏会话标题前显示短 ID 和 UUIDv7 创建时间，方便定位历史会话。":
     "Show a short ID and UUIDv7 creation time before session titles in the sidebar to help locate past sessions.",
   "基础设置": "Basic settings",
diff --git a/assets/inject/renderer-inject.js b/assets/inject/renderer-inject.js
index f4d4c70d1..7553c0379 100644
--- a/assets/inject/renderer-inject.js
+++ b/assets/inject/renderer-inject.js
@@ -3540,7 +3540,7 @@
               <button type="button" class="codex-plus-toggle" data-codex-plus-setting="petRealMouseLook"><span></span></button>
             </div>` : ""}
             <div class="codex-plus-row">
-              <div><div class="codex-plus-row-title">Stepwise</div><div class="codex-plus-row-description">在当前 Codex 页面显示可拖动的下一步建议浮层，可在设置页配置模型和直接发送。</div></div>
+              <div><div class="codex-plus-row-title">Stepwise</div><div class="codex-plus-row-description">在当前 Codex 页面显示可拖动的下一步建议浮层，可在设置页配置模型和直接发送。启停后需重启 Codex++ 生效。</div></div>
               <button type="button" class="codex-plus-toggle" data-codex-plus-setting="stepwise"><span></span></button>
             </div>
             <div class="codex-plus-row" data-codex-service-tier-controls="true">
diff --git a/assets/inject/stepwise-inject.js b/assets/inject/stepwise-inject.js
index 0b4e0015a..e03ceec54 100644
--- a/assets/inject/stepwise-inject.js
+++ b/assets/inject/stepwise-inject.js
@@ -62,6 +62,10 @@
     return !state.destroyed && window[API_KEY]?.instanceId === INSTANCE_ID;
   }
 
+  function stepwiseEnabled() {
+    return state.settings?.enabled === true;
+  }
+
   function normalizeText(value) {
     return String(value || "")
       .replace(/\u00a0/g, " ")
@@ -914,7 +918,7 @@
   }
 
   function installFloat() {
-    if (!isCurrentInstance()) return;
+    if (!isCurrentInstance() || !stepwiseEnabled()) return;
     document.querySelectorAll?.(`[${ROOT_ATTR}="true"]`).forEach((node) => {
       if (node !== state.root) node.remove();
     });
@@ -1757,6 +1761,7 @@
   }
 
   function requestBridgeStepwise(key, userText, assistantText) {
+    if (!stepwiseEnabled()) return;
     if (!key || state.bridgePendingHash === key || state.bridgeCache.has(key)) return;
 
     state.bridgePendingHash = key;
@@ -2029,6 +2034,10 @@
 
   function scan() {
     if (!isCurrentInstance()) return;
+    if (!stepwiseEnabled()) {
+      stopRuntime();
+      return;
+    }
     state.timer = 0;
     state.scans += 1;
     installStyle();
@@ -2106,12 +2115,16 @@
 
   function scheduleScan(delay = SCAN_DELAY_MS) {
     if (!isCurrentInstance()) return;
+    if (!stepwiseEnabled()) {
+      stopRuntime();
+      return;
+    }
     if (state.timer) window.clearTimeout(state.timer);
     state.timer = window.setTimeout(scan, delay);
   }
 
   function installObserver() {
-    if (!isCurrentInstance()) return false;
+    if (!isCurrentInstance() || !stepwiseEnabled()) return false;
     const root = document.body || document.documentElement;
     if (!root) return false;
 
@@ -2147,13 +2160,17 @@
   }
 
   function activateRuntime() {
+    if (!stepwiseEnabled()) {
+      stopRuntime();
+      return;
+    }
     installStyle();
     installFloat();
     if (!state.observer && !installObserver()) {
       document.addEventListener(
         "DOMContentLoaded",
         () => {
-          if (!isCurrentInstance()) return;
+          if (!isCurrentInstance() || !stepwiseEnabled()) return;
           installObserver();
           installFloat();
           void ensureSettings();
diff --git a/crates/codex-plus-core/src/assets.rs b/crates/codex-plus-core/src/assets.rs
index 4bc058b8a..bc95a154a 100644
--- a/crates/codex-plus-core/src/assets.rs
+++ b/crates/codex-plus-core/src/assets.rs
@@ -340,6 +340,11 @@ pub fn injection_script_with_settings(helper_port: u16, settings: &BackendSettin
     let paste_fix = paste_fix_enabled_config(settings);
     let force_chinese_locale = force_chinese_locale_config(settings);
     let fast_startup = fast_startup_config(settings);
+    let stepwise_runtime = if settings.codex_app_stepwise_enabled {
+        stepwise_script()
+    } else {
+        ""
+    };
     format!(
         "window.__CODEX_SESSION_DELETE_HELPER__ = {};\nwindow.__CODEX_PLUS_SPONSOR_IMAGES__ = {};\nwindow.__CODEX_PLUS_VERSION__ = {};\nwindow.__CODEX_PLUS_BUILD__ = {};\nwindow.__CODEX_PLUS_IMAGE_OVERLAY__ = {};\nwindow.__CODEX_PLUS_PLUGIN_MARKETPLACES__ = {};\nwindow.__CODEX_PLUS_EXTERNAL_DREAM_SKIN_RUNTIME__ = true;\nwindow.__CODEX_PLUS_DREAM_SKIN_PLATFORM__ = {};\nwindow.__CODEX_PLUS_DREAM_SKIN_REVISION__ = {};\nwindow.__CODEX_PLUS_DREAM_SKIN_ART__ = {};\nwindow.__CODEX_PLUS_DREAM_SKIN_ART_SIGNATURE__ = {};\nwindow.__CODEX_PLUS_DREAM_SKIN_THEME__ = {};\nwindow.__CODEX_PLUS_PASTE_FIX__ = {};\nwindow.__CODEX_PLUS_FORCE_CHINESE_LOCALE__ = {};\nwindow.__CODEX_PLUS_FAST_STARTUP__ = {};\n{}\n{}\n{}",
         serde_json::to_string(&helper_url).expect("helper URL should serialize"),
@@ -360,7 +365,7 @@ pub fn injection_script_with_settings(helper_port: u16, settings: &BackendSettin
             .expect("force Chinese locale config should serialize"),
         serde_json::to_string(&fast_startup).expect("fast startup config should serialize"),
         renderer_script(),
-        stepwise_script(),
+        stepwise_runtime,
         dream_skin_target_runtime,
     )
 }
diff --git a/crates/codex-plus-core/tests/cdp_bridge.rs b/crates/codex-plus-core/tests/cdp_bridge.rs
index d988f23f5..a4d60abf8 100644
--- a/crates/codex-plus-core/tests/cdp_bridge.rs
+++ b/crates/codex-plus-core/tests/cdp_bridge.rs
@@ -6,6 +6,7 @@ use codex_plus_core::cdp::{
     is_quick_chat_page_target, list_targets, pick_injectable_codex_page_target, pick_page_target,
     validate_cdp_websocket_url,
 };
+use codex_plus_core::settings::BackendSettings;
 
 use futures_util::{SinkExt, StreamExt};
 use serde_json::json;
@@ -67,6 +68,25 @@ fn injection_script_prefixes_helper_url_and_sponsor_images() {
     assert!(script.contains("data-codex-plus-discord"));
 }
 
+#[test]
+fn injection_script_omits_stepwise_runtime_when_disabled() {
+    let script = assets::injection_script_with_settings(57321, &BackendSettings::default());
+
+    assert!(!script.contains("const API_KEY = \"__codexStepwisePanel\";"));
+    assert!(script.contains("data-codex-plus-setting=\"stepwise\""));
+}
+
+#[test]
+fn injection_script_includes_stepwise_runtime_when_enabled() {
+    let settings = BackendSettings {
+        codex_app_stepwise_enabled: true,
+        ..Default::default()
+    };
+    let script = assets::injection_script_with_settings(57321, &settings);
+
+    assert!(script.contains("const API_KEY = \"__codexStepwisePanel\";"));
+}
+
 #[test]
 fn pet_real_mouse_settings_are_gated_to_windows_in_injected_ui() {
     let script = assets::injection_script(57321);
@@ -699,7 +719,11 @@ fn injection_script_menu_exposes_marketplace_plugin_switch_only() {
 
 #[test]
 fn injection_script_menu_exposes_stepwise_switch_and_syncs_panel() {
-    let script = assets::injection_script(57321);
+    let settings = BackendSettings {
+        codex_app_stepwise_enabled: true,
+        ..Default::default()
+    };
+    let script = assets::injection_script_with_settings(57321, &settings);
 
     assert!(script.contains("stepwise: false"));
     assert!(script.contains("stepwise: \"codexAppStepwiseEnabled\""));
@@ -712,6 +736,18 @@ fn injection_script_menu_exposes_stepwise_switch_and_syncs_panel() {
     assert!(script.contains("activateRuntime();"));
 }
 
+#[test]
+fn stepwise_runtime_stops_work_when_disabled() {
+    let script = assets::stepwise_script().replace("\r\n", "\n");
+
+    assert!(script.contains("function stepwiseEnabled()"));
+    assert!(script.contains("if (!stepwiseEnabled()) {"));
+    assert!(script.contains("stopRuntime();"));
+    assert!(script.contains(
+        "function requestBridgeStepwise(key, userText, assistantText) {\n    if (!stepwiseEnabled()) return;"
+    ));
+}
+
 #[test]
 fn stepwise_direct_send_targets_main_chat_composer() {
     let script = assets::stepwise_script();
diff --git a/docs/plans/2026-07-17-stepwise-disabled-injection-design.md b/docs/plans/2026-07-17-stepwise-disabled-injection-design.md
new file mode 100644
index 000000000..bc3d4008c
--- /dev/null
+++ b/docs/plans/2026-07-17-stepwise-disabled-injection-design.md
@@ -0,0 +1,37 @@
+# Stepwise Disabled Injection Design
+
+## Goal
+
+Prevent Codex++ from injecting the Stepwise runtime when Stepwise is disabled, and
+ensure a runtime that was already active cannot recreate its floating UI after the
+setting is turned off.
+
+## Current Behavior
+
+`injection_script_with_settings` always appends `stepwise_script()`. The injected
+runtime loads settings later, so a disabled setting blocks the backend request but
+does not prevent the Stepwise code from reaching the Codex page. Existing delayed
+scan and DOM-ready paths can create UI after the feature is disabled.
+
+## Design
+
+The launcher already passes `BackendSettings` to `injection_script_with_settings`.
+Use `codex_app_stepwise_enabled` there to append the Stepwise script only when it
+is enabled. The renderer menu uses optional chaining for the Stepwise panel, so it
+continues to render and persist the toggle when the runtime is absent.
+
+The Stepwise runtime will additionally guard scan scheduling and DOM-ready work
+with `state.settings?.enabled === true`. Its disabled path will call
+`stopRuntime()`, which removes the root, style, observer, and timer.
+
+Changing the setting changes the new-document bundle, so the UI copy will state
+that restarting Codex++ is required for the change to take effect.
+
+## Validation
+
+- A disabled settings bundle must not contain a Stepwise runtime marker.
+- An enabled settings bundle must contain the Stepwise runtime and the renderer
+  toggle integration.
+- The runtime source must show enabled guards before scan, scheduling, and
+  DOM-ready activation paths.
+- Run the targeted core bridge tests and Rust formatting checks.