diff --git a/client/src/components/Chat/Messages/Content/Parts/Reasoning.tsx b/client/src/components/Chat/Messages/Content/Parts/Reasoning.tsx
index 85d1b00b4b..44d646fcd8 100644
--- a/client/src/components/Chat/Messages/Content/Parts/Reasoning.tsx
+++ b/client/src/components/Chat/Messages/Content/Parts/Reasoning.tsx
@@ -1,4 +1,4 @@
-import { memo, useMemo, useState, useCallback, useRef } from 'react';
+import { memo, useMemo, useState, useCallback, useRef, useId } from 'react';
 import { useAtom } from 'jotai';
 import type { MouseEvent, FocusEvent } from 'react';
 import { ContentTypes } from 'librechat-data-provider';
@@ -36,6 +36,7 @@ type ReasoningProps = {
  * For legacy text-based messages, see Thinking.tsx component.
  */
 const Reasoning = memo(({ reasoning, isLast }: ReasoningProps) => {
+  const contentId = useId();
   const localize = useLocalize();
   const [showThinking] = useAtom(showThinkingAtom);
   const [isExpanded, setIsExpanded] = useState(showThinking);
@@ -104,9 +105,14 @@ const Reasoning = memo(({ reasoning, isLast }: ReasoningProps) => {
             onClick={handleClick}
             label={label}
             content={reasoningText}
+            contentId={contentId}
           />
         </div>
         <div
+          id={contentId}
+          role="group"
+          aria-label={label}
+          aria-hidden={!isExpanded || undefined}
           className={cn(
             'grid transition-all duration-300 ease-out',
             nextType !== ContentTypes.THINK && isExpanded && 'mb-4',
@@ -122,6 +128,7 @@ const Reasoning = memo(({ reasoning, isLast }: ReasoningProps) => {
               isExpanded={isExpanded}
               onClick={handleClick}
               content={reasoningText}
+              contentId={contentId}
             />
           </div>
         </div>
diff --git a/client/src/components/Chat/Messages/Content/Parts/Thinking.tsx b/client/src/components/Chat/Messages/Content/Parts/Thinking.tsx
index 0c5992f4ab..7641738c15 100644
--- a/client/src/components/Chat/Messages/Content/Parts/Thinking.tsx
+++ b/client/src/components/Chat/Messages/Content/Parts/Thinking.tsx
@@ -1,4 +1,4 @@
-import { useState, useMemo, memo, useCallback, useRef, type MouseEvent } from 'react';
+import { useState, useMemo, memo, useCallback, useRef, useId, type MouseEvent } from 'react';
 import { useAtomValue } from 'jotai';
 import { Clipboard, CheckMark, TooltipAnchor } from '@librechat/client';
 import { Lightbulb, ChevronDown, ChevronUp } from 'lucide-react';
@@ -35,12 +35,14 @@ export const ThinkingButton = memo(
     onClick,
     label,
     content,
+    contentId,
     showCopyButton = true,
   }: {
     isExpanded: boolean;
     onClick: (e: MouseEvent<HTMLButtonElement>) => void;
     label: string;
     content?: string;
+    contentId: string;
     showCopyButton?: boolean;
   }) => {
     const localize = useLocalize();
@@ -66,6 +68,7 @@ export const ThinkingButton = memo(
           type="button"
           onClick={onClick}
           aria-expanded={isExpanded}
+          aria-controls={contentId}
           className={cn(
             'group/button flex flex-1 items-center justify-start rounded-lg leading-[18px]',
             fontSize,
@@ -132,11 +135,13 @@ export const FloatingThinkingBar = memo(
     isExpanded,
     onClick,
     content,
+    contentId,
   }: {
     isVisible: boolean;
     isExpanded: boolean;
     onClick: (e: MouseEvent<HTMLButtonElement>) => void;
     content?: string;
+    contentId: string;
   }) => {
     const localize = useLocalize();
     const [isCopied, setIsCopied] = useState(false);
@@ -176,6 +181,8 @@ export const FloatingThinkingBar = memo(
               tabIndex={isVisible ? 0 : -1}
               onClick={onClick}
               aria-label={collapseTooltip}
+              aria-expanded={isExpanded}
+              aria-controls={contentId}
               className={cn(
                 'flex items-center justify-center rounded-lg bg-surface-secondary p-1.5 text-text-secondary-alt shadow-sm',
                 'hover:bg-surface-hover hover:text-text-primary',
@@ -240,6 +247,7 @@ const Thinking: React.ElementType = memo(({ children }: { children: React.ReactN
   const [isExpanded, setIsExpanded] = useState(showThinking);
   const [isBarVisible, setIsBarVisible] = useState(false);
   const containerRef = useRef<HTMLDivElement>(null);
+  const contentId = useId();
 
   const handleClick = useCallback((e: MouseEvent<HTMLButtonElement>) => {
     e.preventDefault();
@@ -295,9 +303,14 @@ const Thinking: React.ElementType = memo(({ children }: { children: React.ReactN
           onClick={handleClick}
           label={label}
           content={textContent}
+          contentId={contentId}
         />
       </div>
       <div
+        id={contentId}
+        role="group"
+        aria-label={label}
+        aria-hidden={!isExpanded || undefined}
         className={cn('grid transition-all duration-300 ease-out', isExpanded && 'mb-8')}
         style={{
           gridTemplateRows: isExpanded ? '1fr' : '0fr',
@@ -310,6 +323,7 @@ const Thinking: React.ElementType = memo(({ children }: { children: React.ReactN
             isExpanded={isExpanded}
             onClick={handleClick}
             content={textContent}
+            contentId={contentId}
           />
         </div>
       </div>
@@ -322,4 +336,4 @@ ThinkingContent.displayName = 'ThinkingContent';
 FloatingThinkingBar.displayName = 'FloatingThinkingBar';
 Thinking.displayName = 'Thinking';
 
-export default memo(Thinking);
+export default Thinking;