diff --git a/ui/src/components/AssistantChat.tsx b/ui/src/components/AssistantChat.tsx
index 8f438a1..a2d7ba8 100644
--- a/ui/src/components/AssistantChat.tsx
+++ b/ui/src/components/AssistantChat.tsx
@@ -134,7 +134,8 @@ export function AssistantChat({
   }
 
   const handleKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
-    if (e.key === 'Enter' && !e.shiftKey) {
+    // Skip if composing (e.g., Japanese IME input)
+    if (e.key === 'Enter' && !e.shiftKey && !e.nativeEvent.isComposing) {
       e.preventDefault()
       handleSend()
     }
diff --git a/ui/src/components/ExpandProjectChat.tsx b/ui/src/components/ExpandProjectChat.tsx
index 52926cb..2eb30b3 100644
--- a/ui/src/components/ExpandProjectChat.tsx
+++ b/ui/src/components/ExpandProjectChat.tsx
@@ -88,7 +88,8 @@ export function ExpandProjectChat({
   }
 
   const handleKeyDown = (e: React.KeyboardEvent) => {
-    if (e.key === 'Enter' && !e.shiftKey) {
+    // Skip if composing (e.g., Japanese IME input)
+    if (e.key === 'Enter' && !e.shiftKey && !e.nativeEvent.isComposing) {
       e.preventDefault()
       handleSendMessage()
     }
diff --git a/ui/src/components/FolderBrowser.tsx b/ui/src/components/FolderBrowser.tsx
index c3e998a..8641bdd 100644
--- a/ui/src/components/FolderBrowser.tsx
+++ b/ui/src/components/FolderBrowser.tsx
@@ -269,7 +269,8 @@ export function FolderBrowser({ onSelect, onCancel, initialPath }: FolderBrowser
                     className="flex-1"
                     autoFocus
                     onKeyDown={(e) => {
-                      if (e.key === 'Enter') handleCreateFolder()
+                      // Skip if composing (e.g., Japanese IME input)
+                      if (e.key === 'Enter' && !e.nativeEvent.isComposing) handleCreateFolder()
                       if (e.key === 'Escape') {
                         setIsCreatingFolder(false)
                         setNewFolderName('')
diff --git a/ui/src/components/SpecCreationChat.tsx b/ui/src/components/SpecCreationChat.tsx
index 1aa804a..24d0c09 100644
--- a/ui/src/components/SpecCreationChat.tsx
+++ b/ui/src/components/SpecCreationChat.tsx
@@ -127,7 +127,8 @@ export function SpecCreationChat({
   }
 
   const handleKeyDown = (e: React.KeyboardEvent) => {
-    if (e.key === 'Enter' && !e.shiftKey) {
+    // Skip if composing (e.g., Japanese IME input)
+    if (e.key === 'Enter' && !e.shiftKey && !e.nativeEvent.isComposing) {
       e.preventDefault()
       handleSendMessage()
     }
diff --git a/ui/src/components/TerminalTabs.tsx b/ui/src/components/TerminalTabs.tsx
index 2771dec..760d69d 100644
--- a/ui/src/components/TerminalTabs.tsx
+++ b/ui/src/components/TerminalTabs.tsx
@@ -96,7 +96,8 @@ export function TerminalTabs({
   // Handle key events during editing
   const handleKeyDown = useCallback(
     (e: React.KeyboardEvent) => {
-      if (e.key === 'Enter') {
+      // Skip if composing (e.g., Japanese IME input)
+      if (e.key === 'Enter' && !e.nativeEvent.isComposing) {
         e.preventDefault()
         submitEdit()
       } else if (e.key === 'Escape') {