diff --git a/browser-extension/src/@types/backend-api.d.ts b/browser-extension/src/@types/backend-api.d.ts
index 415c74cf..a637484c 100644
--- a/browser-extension/src/@types/backend-api.d.ts
+++ b/browser-extension/src/@types/backend-api.d.ts
@@ -10,3 +10,8 @@ export type CreateSystemContextRequest = {
 };
 
 export type GetSystemContextsRequest = (PrimaryKey & SystemContext)[];
+
+export type StreamingChunk = {
+  text: string;
+  stopReason?: string;
+};
diff --git a/browser-extension/src/app/features/chat/ChatMessage.tsx b/browser-extension/src/app/features/chat/ChatMessage.tsx
index 45401495..cd210ca0 100644
--- a/browser-extension/src/app/features/chat/ChatMessage.tsx
+++ b/browser-extension/src/app/features/chat/ChatMessage.tsx
@@ -19,7 +19,7 @@ const ChatMessage: React.FC<Props> = (props) => {
       className={twMerge(
         'border-t last:border-b p-2',
         isUser ? 'bg-aws-squid-ink brightness-150' : '',
-        props.className,
+        props.className
       )}
     >
       {message.title && (
@@ -39,7 +39,7 @@ const ChatMessage: React.FC<Props> = (props) => {
         className={twMerge(
           'transition-all ',
           message.role === 'system' && isOpen && 'max-h-[300px] overflow-y-auto',
-          message.role === 'system' && !isOpen && 'max-h-0 overflow-hidden',
+          message.role === 'system' && !isOpen && 'max-h-0 overflow-hidden'
         )}
       >
         {message.content.split('\n').map((c, idx) => (
diff --git a/browser-extension/src/app/features/chat/chatSlice.ts b/browser-extension/src/app/features/chat/chatSlice.ts
index 2587174c..5ddadf9c 100644
--- a/browser-extension/src/app/features/chat/chatSlice.ts
+++ b/browser-extension/src/app/features/chat/chatSlice.ts
@@ -34,6 +34,13 @@ export const chatSlice = createSlice({
       setInitialStateIfNeeded(state, action.payload.tabId);
       state[action.payload.tabId].messages = action.payload.messages;
     },
+    updateMessageContent: (
+      state,
+      action: PayloadAction<TabId & { index: number; content: string }>
+    ) => {
+      setInitialStateIfNeeded(state, action.payload.tabId);
+      state[action.payload.tabId].messages[action.payload.index].content = action.payload.content;
+    },
     clearMessages: (state, action: PayloadAction<TabId>) => {
       setInitialStateIfNeeded(state, action.payload.tabId);
       state[action.payload.tabId].messages = [];
@@ -41,7 +48,7 @@ export const chatSlice = createSlice({
   },
 });
 
-export const { setMessages, clearMessages } = chatSlice.actions;
+export const { setMessages, updateMessageContent, clearMessages } = chatSlice.actions;
 
 export const chatMessages = (state: RootState, tabId: number) => {
   setInitialStateIfNeeded(state.chat, tabId);
@@ -56,7 +63,7 @@ export const replaceMessages =
       setMessages({
         tabId,
         messages,
-      }),
+      })
     );
   };
 
@@ -71,7 +78,7 @@ export const pushMessages =
         messages: produce(currentMessages, (draft) => {
           draft.push(...messages);
         }),
-      }),
+      })
     );
   };
 
@@ -84,12 +91,11 @@ export const overwriteLatestMessage =
       return;
     }
     dispatch(
-      setMessages({
+      updateMessageContent({
         tabId,
-        messages: produce(currentMessages, (draft) => {
-          draft[draft.length - 1].content = content.replace(/<([^>]+)>([\s\S]*?)<\/\1>/, '$2');
-        }),
-      }),
+        index: currentMessages.length - 1,
+        content: content.replace(/<([^>]+)>([\s\S]*?)<\/\1>/, '$2'),
+      })
     );
   };
 
diff --git a/browser-extension/src/app/features/chat/useChat.ts b/browser-extension/src/app/features/chat/useChat.ts
index 879ad9b1..52c1edb0 100644
--- a/browser-extension/src/app/features/chat/useChat.ts
+++ b/browser-extension/src/app/features/chat/useChat.ts
@@ -11,6 +11,7 @@ import usePredict from './usePredict';
 import { Message } from '../../../@types/chat';
 import Browser from 'webextension-polyfill';
 import { PromptSetting } from '../../../@types/settings';
+import { StreamingChunk } from '../../../@types/backend-api';
 
 const useChat = () => {
   // 複数のタブで起動する場合があるので、タブごとに状態を管理する
@@ -83,14 +84,20 @@ const useChat = () => {
                   role: 'assistant',
                   content: '▍',
                 },
-              ]),
+              ])
         );
 
         // Assistant の発言を更新
         let tmpChunk = '';
 
-        for await (const chunk of stream) {
-          tmpChunk += chunk;
+        for await (const chunks of stream) {
+          // チャンクデータは改行コード区切りで送信されてくるので、分割して処理する
+          for (const chunk_ of chunks.split('\n')) {
+            if (chunk_) {
+              const chunk: StreamingChunk = JSON.parse(chunk_);
+              tmpChunk += chunk.text;
+            }
+          }
 
           // chunk は 10 文字以上でまとめて処理する
           // バッファリングしないと以下のエラーが出る
diff --git a/browser-extension/src/app/features/highlight-menu/HighlightMenu.tsx b/browser-extension/src/app/features/highlight-menu/HighlightMenu.tsx
index b466c401..bf593181 100644
--- a/browser-extension/src/app/features/highlight-menu/HighlightMenu.tsx
+++ b/browser-extension/src/app/features/highlight-menu/HighlightMenu.tsx
@@ -5,7 +5,6 @@ import {
   useInteractions,
   flip,
   shift,
-  inline,
   autoUpdate,
   autoPlacement,
 } from '@floating-ui/react';
@@ -25,9 +24,16 @@ const HighlightMenu: React.FC<Props> = (props) => {
   // https://floating-ui.com/docs/react-examples
   const { refs, floatingStyles, context } = useFloating({
     placement: 'bottom',
+    transform: true,
     open: isOpen,
     onOpenChange: setIsOpen,
-    middleware: [inline(), flip(), shift(), autoPlacement()],
+    middleware: [
+      flip(),
+      shift(),
+      autoPlacement({
+        allowedPlacements: ['top', 'top-start', 'top-end', 'bottom', 'bottom-start', 'bottom-end'],
+      }),
+    ],
     whileElementsMounted: autoUpdate,
   });
 
@@ -99,10 +105,11 @@ const HighlightMenu: React.FC<Props> = (props) => {
           ref={refs.setFloating}
           style={{
             ...floatingStyles,
+            zIndex: 9999999999999,
           }}
           {...getFloatingProps()}
         >
-          <div className="">
+          <div>
             {isOpenContextList ? (
               <PromptList
                 onClick={(systemContext) => {
@@ -111,18 +118,17 @@ const HighlightMenu: React.FC<Props> = (props) => {
               />
             ) : (
               <button
-                className="py-2 rounded-full px-4 bg-aws-squid-ink text-white"
+                className="rounded-full p-2 py-3 bg-aws-squid-ink text-white"
                 onClick={() => {
                   setContent(window.getSelection()?.toString() ?? '');
                   setIsOpenContextList(true);
                 }}
               >
                 {/* Integration先のフォント設置に影響を受けるのでピクセル指定 */}
-                <div className="flex items-center gap-2 text-[13px]">
+                <div className="flex items-center">
                   <div className="rounded">
                     <AwsLogo className="h-[13px]" />
                   </div>
-                  <div className="inline">Bedrock連携</div>
                 </div>
               </button>
             )}
diff --git a/browser-extension/src/pages/chat/ChatPage.tsx b/browser-extension/src/pages/chat/ChatPage.tsx
index 9d1f1c41..57ac3ace 100644
--- a/browser-extension/src/pages/chat/ChatPage.tsx
+++ b/browser-extension/src/pages/chat/ChatPage.tsx
@@ -55,7 +55,6 @@ const ChatPage: React.FC = () => {
     if (message.type === 'CONTENT') {
       setContent(message.content);
     } else if (message.type === 'SYSTEM-CONTEXT') {
-      console.log(message);
       setPromptSetting(message.systemContext);
     }
   });
@@ -66,7 +65,6 @@ const ChatPage: React.FC = () => {
     if (message.type === 'CONTENT') {
       setContent(message.content);
     } else if (message.type === 'SYSTEM-CONTEXT') {
-      console.log(message);
       setPromptSetting(message.systemContext);
     }
   });