diff --git a/manifest.firefox.json b/manifest.firefox.json
index 880e480..1aa463a 100644
--- a/manifest.firefox.json
+++ b/manifest.firefox.json
@@ -23,6 +23,17 @@
     "https://grok.x.ai/*",
     "https://x.com/i/grok*",
     "https://gemini.google.com/*",
+    "https://www.perplexity.ai/*",
+    "https://copilot.microsoft.com/*",
+    "https://chat.deepseek.com/*",
+    "https://huggingface.co/chat/*",
+    "https://poe.com/*",
+    "https://github.com/*",
+    "https://gitlab.com/*",
+    "https://www.reddit.com/*",
+    "https://old.reddit.com/*",
+    "https://stackoverflow.com/*",
+    "https://pastebin.com/*",
     "http://localhost/*",
     "http://127.0.0.1/*"
   ],
@@ -39,6 +50,17 @@
         "https://grok.x.ai/*",
         "https://x.com/i/grok*",
         "https://gemini.google.com/*",
+        "https://www.perplexity.ai/*",
+        "https://copilot.microsoft.com/*",
+        "https://chat.deepseek.com/*",
+        "https://huggingface.co/chat/*",
+        "https://poe.com/*",
+        "https://github.com/*",
+        "https://gitlab.com/*",
+        "https://www.reddit.com/*",
+        "https://old.reddit.com/*",
+        "https://stackoverflow.com/*",
+        "https://pastebin.com/*",
         "http://localhost/*",
         "http://127.0.0.1/*"
       ],
diff --git a/manifest.json b/manifest.json
index 8ff33ee..c3427b2 100644
--- a/manifest.json
+++ b/manifest.json
@@ -17,6 +17,17 @@
     "https://grok.x.ai/*",
     "https://x.com/i/grok*",
     "https://gemini.google.com/*",
+    "https://www.perplexity.ai/*",
+    "https://copilot.microsoft.com/*",
+    "https://chat.deepseek.com/*",
+    "https://huggingface.co/chat/*",
+    "https://poe.com/*",
+    "https://github.com/*",
+    "https://gitlab.com/*",
+    "https://www.reddit.com/*",
+    "https://old.reddit.com/*",
+    "https://stackoverflow.com/*",
+    "https://pastebin.com/*",
     "http://localhost/*",
     "http://127.0.0.1/*"
   ],
@@ -33,6 +44,17 @@
         "https://grok.x.ai/*",
         "https://x.com/i/grok*",
         "https://gemini.google.com/*",
+        "https://www.perplexity.ai/*",
+        "https://copilot.microsoft.com/*",
+        "https://chat.deepseek.com/*",
+        "https://huggingface.co/chat/*",
+        "https://poe.com/*",
+        "https://github.com/*",
+        "https://gitlab.com/*",
+        "https://www.reddit.com/*",
+        "https://old.reddit.com/*",
+        "https://stackoverflow.com/*",
+        "https://pastebin.com/*",
         "http://localhost/*",
         "http://127.0.0.1/*"
       ],
diff --git a/src/background/service-worker.js b/src/background/service-worker.js
index ffbdf9f..e0d6ea1 100644
--- a/src/background/service-worker.js
+++ b/src/background/service-worker.js
@@ -21,12 +21,26 @@ const tabCounts = new Map();
 
 // Built-in URL patterns
 const BUILTIN_URL_PATTERNS = [
+  // AI services
   'https://claude.ai/*',
   'https://chatgpt.com/*',
   'https://chat.openai.com/*',
   'https://grok.x.ai/*',
   'https://x.com/i/grok*',
   'https://gemini.google.com/*',
+  'https://www.perplexity.ai/*',
+  'https://copilot.microsoft.com/*',
+  'https://chat.deepseek.com/*',
+  'https://huggingface.co/chat/*',
+  'https://poe.com/*',
+  // Developer & support sites
+  'https://github.com/*',
+  'https://gitlab.com/*',
+  'https://www.reddit.com/*',
+  'https://old.reddit.com/*',
+  'https://stackoverflow.com/*',
+  'https://pastebin.com/*',
+  // Local
   'http://localhost/*',
   'http://127.0.0.1/*',
 ];
diff --git a/src/options/options.js b/src/options/options.js
index 0adafc4..775555e 100644
--- a/src/options/options.js
+++ b/src/options/options.js
@@ -609,7 +609,7 @@ function renderDomains() {
   const domains = settings.customDomains || [];
 
   if (domains.length === 0) {
-    safeHTML(list, '<div style="text-align:center;color:#9ca3af;padding:12px;font-size:13px">No custom domains. Built-in sites (Claude, ChatGPT, Grok, Gemini, localhost) are always active.</div>');
+    safeHTML(list, '<div style="text-align:center;color:#9ca3af;padding:12px;font-size:13px">No custom domains. Built-in sites (Claude, ChatGPT, Gemini, Grok, Perplexity, Copilot, DeepSeek, HuggingChat, Poe, GitHub, GitLab, Reddit, Stack Overflow, Pastebin, localhost) are always active.</div>');
     return;
   }