diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9bec422..2622b61 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,3 +32,4 @@ jobs:
       - run: node --check assets/tmwd_cdp_bridge/background.js
       - run: node --check assets/tmwd_cdp_bridge/content.js
       - run: node --check assets/tmwd_cdp_bridge/popup.js
+      - run: node --test tests/*.test.mjs
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 84794c6..0a1e5b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,12 @@
 
 所有重要变更都会记录在这里。日期使用北京时间自然日。
 
+## 未发布
+
+### 修复
+
+- Chrome 扩展不再全局移除页面 CSP 响应头或 meta 标签；升级时会清理旧版持久化的动态规则，避免与 Tampermonkey 等注入脚本共同导致 YouTube renderer 满载卡死。受 CSP 限制的页面执行继续使用现有 CDP fallback。
+
 ## 已发布
 
 ## v0.3.4 - 2026-05-19
diff --git a/assets/tmwd_cdp_bridge/background.js b/assets/tmwd_cdp_bridge/background.js
index baeee07..89f4dca 100644
--- a/assets/tmwd_cdp_bridge/background.js
+++ b/assets/tmwd_cdp_bridge/background.js
@@ -1,18 +1,19 @@
 // background.js - Cookie + CDP Bridge
+const LEGACY_CSP_RULE_ID = 9999;
+
+async function removeLegacyCspRule() {
+  try {
+    // Dynamic rules survive extension upgrades, so explicitly migrate existing installs.
+    await chrome.declarativeNetRequest.updateDynamicRules({ removeRuleIds: [LEGACY_CSP_RULE_ID] });
+  } catch (e) {
+    console.warn('[TMWD] Failed to remove legacy CSP rule:', e.message);
+  }
+}
+
+removeLegacyCspRule();
 chrome.runtime.onInstalled.addListener(() => {
   console.log('CDP Bridge installed');
-  // Strip CSP headers to allow eval/inline scripts
-  chrome.declarativeNetRequest.updateDynamicRules({
-    removeRuleIds: [9999],
-    addRules: [{
-      id: 9999, priority: 1,
-      action: { type: 'modifyHeaders', responseHeaders: [
-        { header: 'content-security-policy', operation: 'remove' },
-        { header: 'content-security-policy-report-only', operation: 'remove' }
-      ]},
-      condition: { urlFilter: '*', resourceTypes: ['main_frame', 'sub_frame'] }
-    }]
-  });
+  removeLegacyCspRule();
 });
 
 let lastCommandAt = 0;
diff --git a/assets/tmwd_cdp_bridge/content.js b/assets/tmwd_cdp_bridge/content.js
index 63984da..bf40a9a 100644
--- a/assets/tmwd_cdp_bridge/content.js
+++ b/assets/tmwd_cdp_bridge/content.js
@@ -4,9 +4,6 @@ if (window.__agentBrowserCliCleanup) window.__agentBrowserCliCleanup();
 if (window.__agentBrowserCliObserverCleanup) window.__agentBrowserCliObserverCleanup();
 document.querySelectorAll('#agent-browser-cli-ind,#agent-browser-cli-style').forEach(e => e.remove());
 
-// Remove meta CSP tags
-document.querySelectorAll('meta[http-equiv="Content-Security-Policy"]').forEach(e => e.remove());
-
 /**
  * Render a right-side floating badge that reflects the real bridge connection status.
  */
diff --git a/tests/extension_csp_policy.test.mjs b/tests/extension_csp_policy.test.mjs
new file mode 100644
index 0000000..aedc8a4
--- /dev/null
+++ b/tests/extension_csp_policy.test.mjs
@@ -0,0 +1,121 @@
+import assert from 'node:assert/strict';
+import { webcrypto } from 'node:crypto';
+import { readFile } from 'node:fs/promises';
+import test from 'node:test';
+import vm from 'node:vm';
+
+const backgroundPath = new URL('../assets/tmwd_cdp_bridge/background.js', import.meta.url);
+const contentPath = new URL('../assets/tmwd_cdp_bridge/content.js', import.meta.url);
+
+function eventTarget(listeners = []) {
+  return {
+    addListener(listener) {
+      listeners.push(listener);
+    },
+    removeListener() {},
+  };
+}
+
+function createBackgroundContext(dynamicRuleCalls) {
+  const onInstalled = [];
+  const noOpEvent = eventTarget();
+  const chrome = {
+    alarms: {
+      clear: async () => true,
+      create() {},
+      onAlarm: noOpEvent,
+    },
+    debugger: {
+      onDetach: noOpEvent,
+      onEvent: noOpEvent,
+    },
+    declarativeNetRequest: {
+      async updateDynamicRules(update) {
+        dynamicRuleCalls.push(update);
+      },
+    },
+    extension: {
+      async isAllowedFileSchemeAccess() {
+        return false;
+      },
+    },
+    runtime: {
+      getManifest() {
+        return { version: 'test' };
+      },
+      onInstalled: eventTarget(onInstalled),
+      onMessage: noOpEvent,
+      onStartup: noOpEvent,
+    },
+    scripting: {
+      async executeScript() {
+        return [];
+      },
+    },
+    storage: {
+      local: {
+        async get(defaults) {
+          return defaults;
+        },
+        async set() {},
+      },
+    },
+    tabGroups: {
+      async query() {
+        return [];
+      },
+    },
+    tabs: {
+      async query() {
+        return [];
+      },
+      onCreated: noOpEvent,
+      onRemoved: noOpEvent,
+      onUpdated: noOpEvent,
+    },
+  };
+
+  class FakeWebSocket {}
+  FakeWebSocket.CONNECTING = 0;
+  FakeWebSocket.OPEN = 1;
+
+  return {
+    context: vm.createContext({
+      AbortController,
+      WebSocket: FakeWebSocket,
+      chrome,
+      console: { log() {}, warn() {}, error() {} },
+      crypto: webcrypto,
+      fetch: async () => {
+        throw new Error('daemon unavailable in test');
+      },
+      setTimeout: () => 1,
+    }),
+    onInstalled,
+  };
+}
+
+async function flushMicrotasks() {
+  await Promise.resolve();
+  await Promise.resolve();
+}
+
+test('extension startup removes the legacy CSP rule without installing a replacement', async () => {
+  const source = await readFile(backgroundPath, 'utf8');
+  const dynamicRuleCalls = [];
+  const { context, onInstalled } = createBackgroundContext(dynamicRuleCalls);
+
+  vm.runInContext(source, context, { filename: backgroundPath.pathname });
+  await flushMicrotasks();
+
+  assert.deepEqual(JSON.parse(JSON.stringify(dynamicRuleCalls[0])), { removeRuleIds: [9999] });
+  assert.ok(dynamicRuleCalls.every((update) => !('addRules' in update)));
+
+  for (const listener of onInstalled) await listener({ reason: 'update' });
+  assert.ok(dynamicRuleCalls.every((update) => !('addRules' in update)));
+});
+
+test('content script leaves page CSP metadata untouched', async () => {
+  const source = await readFile(contentPath, 'utf8');
+  assert.doesNotMatch(source, /Content-Security-Policy/i);
+});