diff --git a/README.md b/README.md
index 705663f..2ae6dd0 100644
--- a/README.md
+++ b/README.md
@@ -2,9 +2,11 @@ SMSBower Phone Fill Tool
 
 用途：点击扩展图标后，在当前网页右上角打开一个常驻悬浮窗。点一次“获取并填入”就获取一个 SMSBower 手机号，自动填入当前页面最像手机号的输入框，并复制到剪贴板。再次获取会先释放上一个激活，再拿新号替换页面输入框。
 
-本版已集成 FlowPilot 同款切号机制：
-- 页面提示“该电话/手机号已被使用、已绑定、已注册”时，可点“检测报错换号”自动识别，或直接点“已使用换号”；旧号按被拒原因释放，新号自动填入并复制。
-- 页面提示“无法向此电话号码发送验证码”等发送失败时，“检测报错换号”会按可恢复失败换号。
+本版已集成 FlowPilot 同款自动切号机制：
+- 悬浮窗打开后默认开启“自动切号：开”。
+- 页面提示“该电话/手机号已被使用、已绑定、已注册”时，插件会自动识别并切换下一个号码；旧号按被拒原因释放，新号自动填入并复制。
+- 页面提示“无法向此电话号码发送验证码”等发送失败时，插件会自动按可恢复失败换号。
+- “检测报错换号”和“已使用换号”仍保留为手动兜底按钮。
 - 仍然只负责填号/查码/复制，不自动点击目标页面继续按钮。
 
 安装/更新：
@@ -20,9 +22,10 @@ SMSBower Phone Fill Tool
 4. 填 SMSBower API Key、项目代码、价格上下限、国家顺序。
 5. 顶部“获取并填入”会立即拿号并填入。
 6. 再点一次“获取并填入”会释放上一个激活，替换输入框为新手机号。
-7. 如果目标页面拒绝号码：
-   - 先点“检测报错换号”，插件会扫描当前页面文本，识别“已使用/发送验证码失败”等错误并换号；
-   - 如果你已经确认是“号码已使用”，可直接点“已使用换号”。
+7. 如果目标页面拒绝号码，保持悬浮窗打开即可：插件会自动扫描页面错误文本并切换下一个号码。
+   - “自动切号：开/关”可以临时启停自动扫描；
+   - “检测报错换号”用于手动触发一次扫描；
+   - “已使用换号”用于你已经确认号码被使用时立即换号。
 8. 点“获取验证码”后会每 1 秒查询一次当前激活的验证码状态；如果 SMSBower 已收到 STATUS_OK，会显示验证码并停止。点获取新号、保存、刷新国家或取消当前会停止这轮验证码轮询。
 9. 看到验证码后，点“复制验证码”会复制当前显示的验证码。
 10. 国家搜索支持中文别名，例如搜“印度”会出现 India 和 Indonesia。
diff --git a/content.js b/content.js
index c3083df..0aa1c2b 100644
--- a/content.js
+++ b/content.js
@@ -29,6 +29,14 @@
   let panel = null;
   let dragState = null;
   let codePollToken = 0;
+  let autoRotateObserver = null;
+  let autoRotateTimer = null;
+  let autoRotateInFlight = false;
+  let autoRotateEnabled = true;
+  let lastAutoRotateSignature = '';
+  let lastAutoRotateAt = 0;
+  const AUTO_ROTATE_DEBOUNCE_MS = 800;
+  const AUTO_ROTATE_COOLDOWN_MS = 8000;
 
   function stopCodePolling() {
     codePollToken += 1;
@@ -153,7 +161,7 @@
     const btn = $('.sb-fetch');
     if (btn) btn.disabled = true;
     try {
-      await saveSettings();
+      if (!options.skipSave) await saveSettings();
       const reason = options.reason || 'manual_replace';
       const releaseAction = options.releaseAction || (reason === 'phone_number_used' ? 'ban' : 'cancel');
       setStatus(releaseAction === 'ban' ? '正在释放被拒号码并获取新号...' : '正在取消上一个激活并获取新号...');
@@ -180,14 +188,70 @@
     return String(clone.innerText || clone.textContent || '').slice(-12000);
   }
 
-  async function detectAndRotate() {
+  function updateAutoRotateToggle() {
+    const btn = $('.sb-auto-toggle');
+    if (!btn) return;
+    btn.textContent = autoRotateEnabled ? '自动切号：开' : '自动切号：关';
+    btn.classList.toggle('sb-auto-on', autoRotateEnabled);
+  }
+
+  function buildAutoRotateSignature(reason, text) {
+    const compact = String(text || '').replace(/\s+/g, ' ').trim();
+    return `${reason}:${compact.slice(-220)}`;
+  }
+
+  async function rotateFromClassifiedError(classified, source = 'manual') {
+    const text = getPageTextForPhoneError();
+    const signature = buildAutoRotateSignature(classified.reason, text);
+    const now = Date.now();
+    if (autoRotateInFlight) return false;
+    if (source === 'auto' && signature === lastAutoRotateSignature && now - lastAutoRotateAt < AUTO_ROTATE_COOLDOWN_MS) {
+      return false;
+    }
+    autoRotateInFlight = true;
+    lastAutoRotateSignature = signature;
+    lastAutoRotateAt = now;
+    try {
+      setStatus(source === 'auto'
+        ? `检测到${classified.reason === 'phone_number_used' ? '号码已使用' : '验证码发送失败'}，正在自动切号...`
+        : '检测到手机号错误，正在切号...');
+      await fetchAndFill({ reason: classified.reason, releaseAction: classified.releaseAction, skipSave: true });
+      return true;
+    } finally {
+      autoRotateInFlight = false;
+    }
+  }
+
+  async function detectAndRotate(source = 'manual') {
     const text = getPageTextForPhoneError();
     const classified = await send('CLASSIFY_PHONE_ERROR', { text });
     if (!classified.matched) {
-      setStatus('未检测到明确的手机号错误，可用“手动换号”。', true);
-      return;
+      if (source !== 'auto') setStatus('未检测到明确的手机号错误。', true);
+      return false;
     }
-    await fetchAndFill({ reason: classified.reason, releaseAction: classified.releaseAction });
+    return rotateFromClassifiedError(classified, source);
+  }
+
+  function scheduleAutoRotateCheck() {
+    if (!autoRotateEnabled || autoRotateInFlight) return;
+    if (autoRotateTimer) clearTimeout(autoRotateTimer);
+    autoRotateTimer = setTimeout(() => {
+      autoRotateTimer = null;
+      detectAndRotate('auto').catch((error) => setStatus(error.message || String(error), true));
+    }, AUTO_ROTATE_DEBOUNCE_MS);
+  }
+
+  function startAutoRotateObserver() {
+    if (autoRotateObserver) return;
+    autoRotateObserver = new MutationObserver((mutations) => {
+      if (!autoRotateEnabled) return;
+      if (mutations.some((m) => m.target && panel && panel.contains(m.target))) return;
+      scheduleAutoRotateCheck();
+    });
+    if (document.body) {
+      autoRotateObserver.observe(document.body, { childList: true, subtree: true, characterData: true });
+    }
+    window.addEventListener('focus', scheduleAutoRotateCheck);
   }
 
   async function cancelActive() {
@@ -328,6 +392,7 @@
       #${PANEL_ID} code { color: #67e8f9; user-select: all; }
       #${PANEL_ID} .sb-hint { margin: 7px 0 0; color: #94a3b8; font-size: 12px; }
       #${PANEL_ID} .sb-status { color: #bbf7d0; }
+      #${PANEL_ID} .sb-auto-on { border-color: #22c55e; color: #bbf7d0; }
     `;
     document.documentElement.appendChild(style);
   }
@@ -342,6 +407,7 @@
         <button class="sb-close" type="button" title="隐藏">×</button>
       </div>
       <button class="sb-fetch sb-primary sb-top-fetch" type="button">获取并填入</button>
+      <button class="sb-auto-toggle sb-auto-on" type="button">自动切号：开</button>
       <label>API Key <input class="sb-api-key" type="password" placeholder="SMSBower API Key" /></label>
       <label>API 地址 <input class="sb-base-url" type="url" /></label>
       <div class="sb-row">
@@ -376,13 +442,22 @@
     document.documentElement.appendChild(panel);
     bindPanelEvents();
     await loadSettingsIntoPanel();
+    updateAutoRotateToggle();
+    startAutoRotateObserver();
+    scheduleAutoRotateCheck();
   }
 
   function bindPanelEvents() {
     $('.sb-close').addEventListener('click', () => { panel.style.display = 'none'; });
     $('.sb-save').addEventListener('click', saveSettings);
     $('.sb-fetch').addEventListener('click', () => fetchAndFill({ reason: 'manual_replace', releaseAction: 'cancel' }));
-    $('.sb-rotate-detect').addEventListener('click', detectAndRotate);
+    $('.sb-auto-toggle').addEventListener('click', () => {
+      autoRotateEnabled = !autoRotateEnabled;
+      updateAutoRotateToggle();
+      setStatus(autoRotateEnabled ? '自动切号已开启' : '自动切号已关闭');
+      if (autoRotateEnabled) scheduleAutoRotateCheck();
+    });
+    $('.sb-rotate-detect').addEventListener('click', () => detectAndRotate('manual'));
     $('.sb-rotate-used').addEventListener('click', () => fetchAndFill({ reason: 'phone_number_used', releaseAction: 'ban' }));
     $('.sb-cancel').addEventListener('click', cancelActive);
     $('.sb-code').addEventListener('click', fetchAndCopyCode);
diff --git a/tests/provider.test.js b/tests/provider.test.js
index 4724863..4617103 100644
--- a/tests/provider.test.js
+++ b/tests/provider.test.js
@@ -25,7 +25,7 @@ function load(extra = {}) {
     Set,
     ...extra,
   };
-  const fn = new Function('globalThis', 'self', `with (globalThis) { ${source}; return { collectPriceEntries, filterPriceEntries, normalizeActivation, extractVerificationCode, isPhoneNumberUsedError, isPhoneNumberDeliveryRefusedError, getPhoneReplacementReleaseAction, fetchNextPhone, normalizeSettings }; }`);
+  const fn = new Function('globalThis', 'self', `with (globalThis) { ${source}; return { collectPriceEntries, filterPriceEntries, normalizeActivation, extractVerificationCode, isPhoneNumberUsedError, isPhoneNumberDeliveryRefusedError, getPhoneReplacementReleaseAction, fetchNextPhone, normalizeSettings, buildUrl }; }`);
   return fn(sandbox, sandbox);
 }
 test('collectPriceEntries parses keyed price inventory', () => {
@@ -53,10 +53,25 @@ test('extractVerificationCode parses STATUS_OK response', () => {
 test('FlowPilot-style phone failure classifiers choose release action', () => {
   const api = load();
   assert.equal(api.isPhoneNumberUsedError('该电话已被使用，请换一个号码'), true);
+  assert.equal(api.isPhoneNumberUsedError('手机号已绑定，请换一个号码'), true);
   assert.equal(api.isPhoneNumberDeliveryRefusedError('无法向此电话号码发送验证码'), true);
   assert.equal(api.getPhoneReplacementReleaseAction('phone_number_used'), 'ban');
   assert.equal(api.getPhoneReplacementReleaseAction('phone_delivery_refused'), 'cancel');
 });
+
+test('buildUrl keeps api_key and replacement queries explicit', () => {
+  const api = load();
+  const url = new URL(api.buildUrl(
+    { baseUrl: 'https://smsbower.app/stubs/handler_api.php', apiKey: 'demo-key' },
+    { action: 'getNumberV2', service: 'dr', country: 6, maxPrice: 0.2 }
+  ));
+  assert.equal(url.searchParams.get('api_key'), 'demo-key');
+  assert.equal(url.searchParams.get('action'), 'getNumberV2');
+  assert.equal(url.searchParams.get('service'), 'dr');
+  assert.equal(url.searchParams.get('country'), '6');
+  assert.equal(url.searchParams.get('maxPrice'), '0.2');
+});
+
 test('fetchNextPhone releases previous activation then acquires replacement', async () => {
   const requests = [];
   const stored = {