diff --git a/public/uncloseai.js b/public/uncloseai.js
index 7d0b833..ba12c1b 100644
--- a/public/uncloseai.js
+++ b/public/uncloseai.js
@@ -22,6 +22,12 @@ import * as TTS from "./src/tts.js";
 import * as UI from "./src/ui.js";
 import { UncloseVault } from "./src/vault.js";
 
+// Duplicate load guard: if a page already includes uncloseai.js natively,
+// the extension should not re-initialize. Module exports remain available,
+// but window globals, event listeners, and DOM side effects only run once.
+const __alreadyLoaded = window.__UNCLOSEAI_LOADED__ === true;
+window.__UNCLOSEAI_LOADED__ = true;
+
 // -------------------------
 // Vault Support
 // -------------------------
@@ -120,90 +126,102 @@ export { chatHistory } from "./src/chat.js";
 
 // -------------------------
 // Global Scope Exports (for backward compatibility)
+// Side effects only run once: if the page already loaded uncloseai.js,
+// the extension copy skips initialization but module exports still work.
 // -------------------------
 
-// Export functions to global scope for HTML onclick handlers
-window.handleUserInput = Chat.handleUserInput;
-window.readPageWithHermes = PageReader.readPageWithHermes;
-window.sendMessage = Chat.sendMessage;
-window.speakText = TTS.speakText;
-window.uploadFile = FileUpload.uploadFile;
-window.openTTSModal = UI.openTTSModal;
-window.openTranslateModal = UI.openTranslateModal;
-window.toggleUncloseaiEmbeddedModal = async () =>
-	await UI.toggleUncloseaiEmbeddedModal();
-window.extractWebpageContent = Content.extractWebpageContent;
-window.getSelectedModel = Models.getSelectedModel;
-window.getSelectedModelEndpoint = Models.getSelectedModelEndpoint;
-window.showProgressIndicator = FileUpload.showProgressIndicator;
-window.hideProgressIndicator = FileUpload.hideProgressIndicator;
-window.handleTTSFromElement = UI.handleTTSFromElement;
-window.handleUploadFromElement = UI.handleUploadFromElement;
-window.handleSmartTranslate = UI.handleSmartTranslate;
-window.UncloseVault = UncloseVault;
+if (!__alreadyLoaded) {
+	// Export functions to global scope for HTML onclick handlers
+	window.handleUserInput = Chat.handleUserInput;
+	window.readPageWithHermes = PageReader.readPageWithHermes;
+	window.sendMessage = Chat.sendMessage;
+	window.speakText = TTS.speakText;
+	window.uploadFile = FileUpload.uploadFile;
+	window.openTTSModal = UI.openTTSModal;
+	window.openTranslateModal = UI.openTranslateModal;
+	window.toggleUncloseaiEmbeddedModal = async () =>
+		await UI.toggleUncloseaiEmbeddedModal();
+	window.extractWebpageContent = Content.extractWebpageContent;
+	window.getSelectedModel = Models.getSelectedModel;
+	window.getSelectedModelEndpoint = Models.getSelectedModelEndpoint;
+	window.showProgressIndicator = FileUpload.showProgressIndicator;
+	window.hideProgressIndicator = FileUpload.hideProgressIndicator;
+	window.handleTTSFromElement = UI.handleTTSFromElement;
+	window.handleUploadFromElement = UI.handleUploadFromElement;
+	window.handleSmartTranslate = UI.handleSmartTranslate;
+	window.UncloseVault = UncloseVault;
 
-// Initialize on page load
-window.addEventListener("load", async () => {
-	console.log("uncloseai.js: window.onload event fired.");
+	// Initialize on page load
+	window.addEventListener("load", async () => {
+		console.log("uncloseai.js: window.onload event fired.");
 
-	// Load CryptoJS and initialize vault early
-	await ensureCryptoJS();
-	if (UncloseVault.isAvailable()) {
-		const restored = UncloseVault.init();
-		console.log("uncloseai.js: Vault initialized, session restored:", restored);
-	}
-
-	// Check skip init flag first
-	if (window.UNCLOSEAI_SKIP_INIT === true) {
-		console.log(
-			"uncloseai.js: Skipping full initialization as requested by flag.",
-		);
-		console.log(
-			"uncloseai.js: Creating floating button only for preview windows.",
-		);
-
-		// Still create floating button for preview windows, but skip other initialization
-		const SHOW_FLOATING_BUTTON = window.UNCLOSEAI_FLOATING_BUTTON !== false;
-		if (SHOW_FLOATING_BUTTON) {
-			UI.createFloatingAIButton();
+		// Load CryptoJS and initialize vault early
+		await ensureCryptoJS();
+		if (UncloseVault.isAvailable()) {
+			const restored = UncloseVault.init();
+			console.log(
+				"uncloseai.js: Vault initialized, session restored:",
+				restored,
+			);
 		}
-		return;
-	}
 
-	UI.initializeSystem();
-});
+		// Check skip init flag first
+		if (window.UNCLOSEAI_SKIP_INIT === true) {
+			console.log(
+				"uncloseai.js: Skipping full initialization as requested by flag.",
+			);
+			console.log(
+				"uncloseai.js: Creating floating button only for preview windows.",
+			);
 
-// Export helper functions for class-based integrations
-window.handleCustomChat = async (button) => {
-	const container = button.parentElement;
-	const input = container.querySelector("[data-chat-input]");
-	const chatBox = container.querySelector("[data-chat-box]");
-	const message = input.value.trim();
-
-	if (!message) return;
-
-	// Add user message
-	chatBox.innerHTML += `<div style="margin: 2px 0; padding: 2px; background: #e3f2fd; border-radius: 2px; font-size: 0.9em;"><strong>You:</strong> ${message}</div>`;
-	input.value = "";
-
-	// Add AI thinking indicator
-	const thinkingDiv = document.createElement("div");
-	thinkingDiv.style.cssText =
-		"margin: 2px 0; padding: 2px; background: #f5f5f5; border-radius: 2px; font-size: 0.9em;";
-	thinkingDiv.innerHTML = "<strong>AI:</strong> <em>thinking...</em>";
-	chatBox.appendChild(thinkingDiv);
-	chatBox.scrollTop = chatBox.scrollHeight;
-
-	try {
-		let response = "";
-		for await (const chunk of Chat.sendMessage(message)) {
-			response += chunk;
-			thinkingDiv.innerHTML = `<strong>AI:</strong> ${response}`;
-			chatBox.scrollTop = chatBox.scrollHeight;
+			// Still create floating button for preview windows, but skip other initialization
+			const SHOW_FLOATING_BUTTON =
+				window.UNCLOSEAI_FLOATING_BUTTON !== false;
+			if (SHOW_FLOATING_BUTTON) {
+				UI.createFloatingAIButton();
+			}
+			return;
 		}
-	} catch (error) {
-		thinkingDiv.innerHTML = `<strong>Error:</strong> ${error.message}`;
-	}
-};
 
-console.log("uncloseai.js: Modular version loaded successfully");
+		UI.initializeSystem();
+	});
+
+	// Export helper functions for class-based integrations
+	window.handleCustomChat = async (button) => {
+		const container = button.parentElement;
+		const input = container.querySelector("[data-chat-input]");
+		const chatBox = container.querySelector("[data-chat-box]");
+		const message = input.value.trim();
+
+		if (!message) return;
+
+		// Add user message
+		chatBox.innerHTML += `<div style="margin: 2px 0; padding: 2px; background: #e3f2fd; border-radius: 2px; font-size: 0.9em;"><strong>You:</strong> ${message}</div>`;
+		input.value = "";
+
+		// Add AI thinking indicator
+		const thinkingDiv = document.createElement("div");
+		thinkingDiv.style.cssText =
+			"margin: 2px 0; padding: 2px; background: #f5f5f5; border-radius: 2px; font-size: 0.9em;";
+		thinkingDiv.innerHTML = "<strong>AI:</strong> <em>thinking...</em>";
+		chatBox.appendChild(thinkingDiv);
+		chatBox.scrollTop = chatBox.scrollHeight;
+
+		try {
+			let response = "";
+			for await (const chunk of Chat.sendMessage(message)) {
+				response += chunk;
+				thinkingDiv.innerHTML = `<strong>AI:</strong> ${response}`;
+				chatBox.scrollTop = chatBox.scrollHeight;
+			}
+		} catch (error) {
+			thinkingDiv.innerHTML = `<strong>Error:</strong> ${error.message}`;
+		}
+	};
+
+	console.log("uncloseai.js: Modular version loaded successfully");
+} else {
+	console.log(
+		"uncloseai.js: page already has uncloseai loaded, skipping duplicate initialization",
+	);
+}