diff --git a/src/bot/chatProcedure.ts b/src/bot/chatProcedure.ts
index 2710ea1..1e8e8a4 100644
--- a/src/bot/chatProcedure.ts
+++ b/src/bot/chatProcedure.ts
@@ -48,8 +48,35 @@ export class ChatProcedure {
 
   /**
    * Open the chat panel by clicking the chat button.
+   * In authenticated Teams, the chat panel may already be open (meeting loads
+   * from a chat thread). Clicking again would TOGGLE it closed.
    */
   private async _openChatPanel(): Promise<void> {
+    // Check if chat panel is already open before clicking (avoid toggle-off)
+    const alreadyOpen = await this._page.evaluate(() => {
+      const chatBtn = document.querySelector('button[id="chat-button"], button[data-tid="chat-button"]') as HTMLElement | null;
+      if (chatBtn) {
+        // Teams toggle buttons use aria-pressed="true" when active
+        if (chatBtn.getAttribute('aria-pressed') === 'true') return true;
+      }
+      // Also check if chat input or message list is visible (panel is open)
+      const chatInput = document.querySelector(
+        '[data-tid="ckeditor-replyConversation"], div[role="textbox"][data-tid*="chat"], div[role="textbox"][aria-label*="message" i]'
+      ) as HTMLElement | null;
+      if (chatInput && chatInput.offsetHeight > 0) return true;
+      // Check if message list container is visible
+      const messageList = document.querySelector(
+        '[data-tid="message-pane-list"], [data-tid="chat-pane-list"], [data-tid="chat-pane"]'
+      ) as HTMLElement | null;
+      if (messageList && messageList.offsetHeight > 50) return true;
+      return false;
+    });
+
+    if (alreadyOpen) {
+      this._logger.info('Chat panel already open - skipping toggle');
+      return;
+    }
+
     const chatButtonSelectors = [
       'button[id="chat-button"]',
       'button[data-tid="chat-button"]',