diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 6d0461d..06dc72a 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -89,6 +89,7 @@ import {
   getShortcutDisplay,
   getShortcutDisplayLabel,
   getShortcutPlatform,
+  installGlobalImeCompositionTracking,
   isEditableElement,
   isShortcutMatch,
   normalizeShortcutCombo,
@@ -1378,6 +1379,9 @@ function App() {
       import.meta.env.DEV,
       import.meta.env.VITE_GONAVI_ENABLE_MAC_WINDOW_DIAGNOSTICS,
   );
+  useEffect(() => {
+      return installGlobalImeCompositionTracking(window, document);
+  }, []);
   const {
       aboutDisplayVersion,
       aboutInfo,
diff --git a/frontend/src/components/QueryEditor.external-sql-save.test.tsx b/frontend/src/components/QueryEditor.external-sql-save.test.tsx
index 16a2194..3725c0d 100644
--- a/frontend/src/components/QueryEditor.external-sql-save.test.tsx
+++ b/frontend/src/components/QueryEditor.external-sql-save.test.tsx
@@ -8,6 +8,7 @@ import { setCurrentLanguage } from '../i18n';
 import { I18nProvider } from '../i18n/provider';
 import type { SavedQuery, TabData } from '../types';
 import { ORACLE_ROWID_LOCATOR_COLUMN } from '../utils/rowLocator';
+import { setGlobalImeCompositionActive } from '../utils/shortcuts';
 import { clearQueryTabDraft, clearSQLFileTabDraft, getQueryTabDraft, getSQLFileTabDraft } from '../utils/sqlFileTabDrafts';
 import QueryEditor, {
   collectQueryEditorObjectDecorationCandidates,
@@ -689,6 +690,7 @@ describe('QueryEditor external SQL save', () => {
     clearQueryTabDraft('tab-2');
     clearSQLFileTabDraft('tab-1');
     clearSQLFileTabDraft('tab-2');
+    setGlobalImeCompositionActive(false);
   });
 
   afterEach(() => {
@@ -3357,6 +3359,97 @@ describe('QueryEditor external SQL save', () => {
     expect(lastDecorationCall?.[1]?.[0]?.options?.inlineClassName).toBe('gonavi-query-editor-link-hint');
   });
 
+  it('ignores IME candidate keydown events when syncing modifier hover state', async () => {
+    const windowListeners: Record<string, ((event?: any) => void)[]> = {};
+    vi.stubGlobal('window', {
+      addEventListener: vi.fn((type: string, listener: (event?: any) => void) => {
+        windowListeners[type] ||= [];
+        windowListeners[type].push(listener);
+      }),
+      removeEventListener: vi.fn(),
+      dispatchEvent: vi.fn(),
+    });
+
+    editorState.value = 'select 1';
+
+    await act(async () => {
+      create(<QueryEditor tab={createTab({ query: editorState.value })} />);
+    });
+
+    editorState.editor.updateOptions.mockClear();
+    editorState.editor.deltaDecorations.mockClear();
+
+    await act(async () => {
+      const imeEvent = {
+        ctrlKey: false,
+        metaKey: false,
+        altKey: false,
+        shiftKey: false,
+        key: 'Process',
+        keyCode: 229,
+        which: 229,
+        isComposing: true,
+        nativeEvent: {
+          isComposing: true,
+          keyCode: 229,
+          which: 229,
+        },
+        preventDefault: vi.fn(),
+        stopPropagation: vi.fn(),
+        target: null,
+      };
+      windowListeners.keydown?.forEach((listener) => listener(imeEvent));
+    });
+
+    expect(editorState.editor.updateOptions).not.toHaveBeenCalledWith({ mouseStyle: 'text' });
+    expect(editorState.editor.deltaDecorations).not.toHaveBeenCalled();
+  });
+
+  it('ignores candidate number keys while a composition session is active', async () => {
+    const windowListeners: Record<string, ((event?: any) => void)[]> = {};
+    vi.stubGlobal('window', {
+      addEventListener: vi.fn((type: string, listener: (event?: any) => void) => {
+        windowListeners[type] ||= [];
+        windowListeners[type].push(listener);
+      }),
+      removeEventListener: vi.fn(),
+      dispatchEvent: vi.fn(),
+    });
+
+    editorState.value = 'select 1';
+
+    await act(async () => {
+      create(<QueryEditor tab={createTab({ query: editorState.value })} />);
+    });
+
+    setGlobalImeCompositionActive(true);
+    editorState.editor.updateOptions.mockClear();
+    editorState.editor.deltaDecorations.mockClear();
+
+    await act(async () => {
+      const candidateSelectEvent = {
+        ctrlKey: false,
+        metaKey: false,
+        altKey: false,
+        shiftKey: false,
+        key: '1',
+        keyCode: 49,
+        which: 49,
+        isComposing: false,
+        nativeEvent: {
+          isComposing: false,
+        },
+        preventDefault: vi.fn(),
+        stopPropagation: vi.fn(),
+        target: null,
+      };
+      windowListeners.keydown?.forEach((listener) => listener(candidateSelectEvent));
+    });
+
+    expect(editorState.editor.updateOptions).not.toHaveBeenCalled();
+    expect(editorState.editor.deltaDecorations).not.toHaveBeenCalled();
+  });
+
   it('keeps query editor hyperlink decorations blue with a solid underline', () => {
     const css = readFileSync(new URL('../App.css', import.meta.url), 'utf8');
 
@@ -3839,6 +3932,183 @@ describe('QueryEditor external SQL save', () => {
     expect(editorState.editor.getModel().getValue).not.toHaveBeenCalled();
   });
 
+  it('ignores focused local tab query echoes so IME candidate commits are not overwritten', async () => {
+    let renderer!: ReactTestRenderer;
+
+    await act(async () => {
+      renderer = create(<QueryEditor tab={createTab({ query: '' })} />);
+    });
+
+    editorState.value = '';
+    editorState.hasTextFocus = true;
+    editorState.editor.setValue.mockClear();
+
+    await act(async () => {
+      editorState.latestOnChange?.('我');
+    });
+
+    editorState.editor.getValue.mockImplementationOnce(() => '');
+    await act(async () => {
+      renderer.update(<QueryEditor tab={createTab({ query: '我' })} />);
+    });
+
+    expect(getQueryTabDraft('tab-1')).toBe('我');
+    expect(editorState.editor.setValue).not.toHaveBeenCalled();
+  });
+
+  it('still applies true external tab query changes while the editor is focused', async () => {
+    let renderer!: ReactTestRenderer;
+
+    await act(async () => {
+      renderer = create(<QueryEditor tab={createTab({ query: '' })} />);
+    });
+
+    editorState.value = '';
+    editorState.hasTextFocus = true;
+    editorState.editor.setValue.mockClear();
+
+    await act(async () => {
+      editorState.latestOnChange?.('我');
+    });
+
+    editorState.editor.getValue.mockImplementationOnce(() => '');
+    await act(async () => {
+      renderer.update(<QueryEditor tab={createTab({ query: 'SELECT 2;' })} />);
+    });
+
+    expect(editorState.editor.setValue).toHaveBeenCalledWith('SELECT 2;');
+  });
+
+  it('recovers committed IME text when Monaco composition end leaves the model unchanged', async () => {
+    vi.useFakeTimers();
+    const domListeners: Record<string, ((event?: any) => void)[]> = {};
+    editorState.domNode.addEventListener.mockImplementation((type: string, listener: (event?: any) => void) => {
+      domListeners[type] ||= [];
+      domListeners[type].push(listener);
+    });
+    editorState.editor.getValue.mockReset();
+    editorState.editor.getValue.mockImplementation(() => editorState.value);
+
+    try {
+      await act(async () => {
+        create(<QueryEditor tab={createTab({ query: "select '';" })} />);
+      });
+
+      editorState.position = { lineNumber: 1, column: 9 };
+      editorState.selection = null;
+      editorState.editor.executeEdits.mockClear();
+
+      await act(async () => {
+        domListeners.compositionstart?.forEach((listener) => listener({ data: '' }));
+        domListeners.compositionend?.forEach((listener) => listener({ data: '我' }));
+      });
+
+      await act(async () => {
+        vi.runOnlyPendingTimers();
+      });
+
+      expect(editorState.editor.executeEdits).toHaveBeenCalledWith(
+        'gonavi-ime-composition-fallback',
+        [{
+          range: expect.objectContaining({
+            startLineNumber: 1,
+            startColumn: 9,
+            endLineNumber: 1,
+            endColumn: 9,
+          }),
+          text: '我',
+          forceMoveMarkers: true,
+        }],
+      );
+      expect(editorState.value).toBe("select '我';");
+      expect(getQueryTabDraft('tab-1')).toBe("select '我';");
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
+  it('does not duplicate IME text when Monaco already applied the composition commit', async () => {
+    vi.useFakeTimers();
+    const domListeners: Record<string, ((event?: any) => void)[]> = {};
+    editorState.domNode.addEventListener.mockImplementation((type: string, listener: (event?: any) => void) => {
+      domListeners[type] ||= [];
+      domListeners[type].push(listener);
+    });
+    editorState.editor.getValue.mockReset();
+    editorState.editor.getValue.mockImplementation(() => editorState.value);
+
+    try {
+      await act(async () => {
+        create(<QueryEditor tab={createTab({ query: "select '';" })} />);
+      });
+
+      editorState.position = { lineNumber: 1, column: 9 };
+      editorState.selection = null;
+      editorState.editor.executeEdits.mockClear();
+
+      await act(async () => {
+        domListeners.compositionstart?.forEach((listener) => listener({ data: '' }));
+        editorState.value = "select '我';";
+        domListeners.compositionend?.forEach((listener) => listener({ data: '我' }));
+      });
+
+      await act(async () => {
+        vi.runOnlyPendingTimers();
+      });
+
+      expect(editorState.editor.executeEdits).not.toHaveBeenCalledWith(
+        'gonavi-ime-composition-fallback',
+        expect.anything(),
+      );
+      expect(editorState.value).toBe("select '我';");
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
+  it('uses beforeinput data as the IME fallback text when composition end data is empty', async () => {
+    vi.useFakeTimers();
+    const domListeners: Record<string, ((event?: any) => void)[]> = {};
+    editorState.domNode.addEventListener.mockImplementation((type: string, listener: (event?: any) => void) => {
+      domListeners[type] ||= [];
+      domListeners[type].push(listener);
+    });
+    editorState.editor.getValue.mockReset();
+    editorState.editor.getValue.mockImplementation(() => editorState.value);
+
+    try {
+      await act(async () => {
+        create(<QueryEditor tab={createTab({ query: "select '';" })} />);
+      });
+
+      editorState.position = { lineNumber: 1, column: 9 };
+      editorState.selection = null;
+      editorState.editor.executeEdits.mockClear();
+
+      await act(async () => {
+        domListeners.compositionstart?.forEach((listener) => listener({ data: '' }));
+        domListeners.beforeinput?.forEach((listener) => listener({
+          data: '我',
+          inputType: 'insertCompositionText',
+          isComposing: true,
+        }));
+        domListeners.compositionend?.forEach((listener) => listener({ data: '' }));
+      });
+
+      await act(async () => {
+        vi.runOnlyPendingTimers();
+      });
+
+      expect(editorState.editor.executeEdits).toHaveBeenCalledWith(
+        'gonavi-ime-composition-fallback',
+        [expect.objectContaining({ text: '我' })],
+      );
+      expect(editorState.value).toBe("select '我';");
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
   it('keeps short regular query typing on the Monaco fast path without rerender side effects', async () => {
     await act(async () => {
       create(<QueryEditor tab={createTab({ query: 'select 1;' })} />);
diff --git a/frontend/src/components/QueryEditor.tsx b/frontend/src/components/QueryEditor.tsx
index 704978c..ab3a346 100644
--- a/frontend/src/components/QueryEditor.tsx
+++ b/frontend/src/components/QueryEditor.tsx
@@ -10,7 +10,7 @@ import { DBQuery, DBQueryWithCancel, DBQueryMulti, DBQueryMultiTransactional, DB
 import { GONAVI_ROW_KEY } from './DataGrid';
 import { getDataSourceCapabilities, shouldShowOceanBaseRowNumberColumn } from '../utils/dataSourceCapabilities';
 import { applyMongoQueryAutoLimit, convertMongoShellToJsonCommand } from "../utils/mongodb";
-import { getShortcutDisplayLabel, getShortcutPlatform, getShortcutPrimaryModifierDisplayLabel, isEditableElement, isShortcutMatch, comboToMonacoKeyBinding, resolveShortcutBinding } from "../utils/shortcuts";
+import { getShortcutDisplayLabel, getShortcutPlatform, getShortcutPrimaryModifierDisplayLabel, isEditableElement, isImeComposingKeyEvent, isShortcutMatch, comboToMonacoKeyBinding, resolveShortcutBinding } from "../utils/shortcuts";
 import { useAutoFetchVisibility } from '../utils/autoFetchVisibility';
 import { buildRpcConnectionConfig } from '../utils/connectionRpcConfig';
 import { isPostgresSchemaDialect } from '../utils/connectionDriverType';
@@ -246,6 +246,15 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
   const aiContextMenuActionDisposablesRef = useRef<any[]>([]);
   const toggleQueryResultsPanelActionRef = useRef<any>(null);
   const lastExternalQueryRef = useRef<string>(getTabQueryValue(tab));
+  const lastLocalQueryRef = useRef<string>(query);
+  const imeCompositionFallbackRef = useRef<{
+      editor: any;
+      valueBefore: string;
+      selectionBefore: any;
+      positionBefore: { lineNumber: number; column: number } | null;
+      committedText: string;
+  } | null>(null);
+  const imeCompositionFallbackTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const lastEditorCursorPositionRef = useRef<any>(null);
   const lastHoverTargetPositionRef = useRef<{ lineNumber: number; column: number } | null>(null);
   const lastExecutedEditorQueryRef = useRef<string>('');
@@ -441,6 +450,7 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
 
   const syncQueryDraft = useCallback((nextQuery: string) => {
       const next = String(nextQuery ?? '');
+      lastLocalQueryRef.current = next;
       if (isExternalSQLFileTab) {
           setSQLFileTabDraft(tab.id, next);
           return;
@@ -881,6 +891,11 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
           return;
       }
       lastExternalQueryRef.current = incoming;
+      const editorHasFocus = editorRef.current?.hasTextFocus?.() === true;
+      if (editorHasFocus && incoming === lastLocalQueryRef.current) {
+          setQuery(incoming);
+          return;
+      }
       syncQueryToEditor(incoming);
   }, [tab.id, tab.query]);
 
@@ -1347,16 +1362,23 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
 
       const syncModifierState = (keyboardEvent?: KeyboardEvent | MouseEvent | null) => {
           const wasPressed = ctrlMetaPressedRef.current;
-          ctrlMetaPressedRef.current = !!(keyboardEvent?.ctrlKey || keyboardEvent?.metaKey);
-          if (!ctrlMetaPressedRef.current) {
+          const isKeyboardLikeEvent = keyboardEvent
+              && typeof keyboardEvent === 'object'
+              && ('key' in keyboardEvent || 'code' in keyboardEvent || 'repeat' in keyboardEvent);
+          if (isKeyboardLikeEvent && isImeComposingKeyEvent(keyboardEvent as KeyboardEvent)) {
+              return;
+          }
+          const nextPressed = !!(keyboardEvent?.ctrlKey || keyboardEvent?.metaKey);
+          ctrlMetaPressedRef.current = nextPressed;
+          if (!nextPressed && !wasPressed) {
+              return;
+          }
+          if (!nextPressed) {
               clearQueryEditorLinkDecorations(editor, linkDecorationIdsRef);
               editor.updateOptions?.({ mouseStyle: 'text' });
               setQueryEditorMouseCursor(editor, '');
               return;
           }
-          const isKeyboardLikeEvent = keyboardEvent
-              && typeof keyboardEvent === 'object'
-              && ('key' in keyboardEvent || 'code' in keyboardEvent || 'repeat' in keyboardEvent);
           if (!wasPressed || isKeyboardLikeEvent) {
               applyNavigationHoverStateAtPosition(lastHoverTargetPositionRef.current);
           }
@@ -1368,6 +1390,103 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
           setQueryEditorMouseCursor(editor, '');
       };
       const editorDomNode = editor.getDomNode?.();
+      const clearImeCompositionFallbackTimer = () => {
+          if (imeCompositionFallbackTimerRef.current !== null) {
+              clearTimeout(imeCompositionFallbackTimerRef.current);
+              imeCompositionFallbackTimerRef.current = null;
+          }
+      };
+      const getEditorText = () => String(
+          editor.getValue?.()
+          ?? editor.getModel?.()?.getValue?.()
+          ?? '',
+      );
+      const buildImeFallbackRange = (snapshot: NonNullable<typeof imeCompositionFallbackRef.current>) => {
+          const selection = snapshot.selectionBefore;
+          const startFromSelection = typeof selection?.getStartPosition === 'function'
+              ? normalizeEditorPosition(selection.getStartPosition())
+              : null;
+          const endFromSelection = typeof selection?.getEndPosition === 'function'
+              ? normalizeEditorPosition(selection.getEndPosition())
+              : null;
+          const startPosition = startFromSelection || normalizeEditorPosition({
+              lineNumber: selection?.startLineNumber ?? selection?.selectionStartLineNumber,
+              column: selection?.startColumn ?? selection?.selectionStartColumn,
+          }) || snapshot.positionBefore || lastEditorCursorPositionRef.current || { lineNumber: 1, column: 1 };
+          const endPosition = endFromSelection || normalizeEditorPosition({
+              lineNumber: selection?.endLineNumber ?? selection?.positionLineNumber,
+              column: selection?.endColumn ?? selection?.positionColumn,
+          }) || startPosition;
+          return new monaco.Range(
+              startPosition.lineNumber,
+              startPosition.column,
+              endPosition.lineNumber,
+              endPosition.column,
+          );
+      };
+      const handleImeCompositionStart = () => {
+          clearImeCompositionFallbackTimer();
+          imeCompositionFallbackRef.current = {
+              editor,
+              valueBefore: getEditorText(),
+              selectionBefore: editor.getSelection?.() || null,
+              positionBefore: normalizeEditorPosition(editor.getPosition?.()) || lastEditorCursorPositionRef.current || null,
+              committedText: '',
+          };
+      };
+      const handleImeBeforeInput = (rawEvent: Event) => {
+          const snapshot = imeCompositionFallbackRef.current;
+          if (!snapshot || snapshot.editor !== editor) {
+              return;
+          }
+          const inputEvent = rawEvent as InputEvent;
+          const nextText = String(inputEvent.data ?? '');
+          if (nextText && (inputEvent.isComposing || String(inputEvent.inputType || '').includes('Composition'))) {
+              snapshot.committedText = nextText;
+          }
+      };
+      const handleImeCompositionEnd = (rawEvent: Event) => {
+          const snapshot = imeCompositionFallbackRef.current;
+          imeCompositionFallbackRef.current = null;
+          const committedText = String((rawEvent as CompositionEvent).data ?? '') || snapshot?.committedText || '';
+          if (!committedText || !snapshot || snapshot.editor !== editor) {
+              return;
+          }
+
+          const fallbackRange = buildImeFallbackRange(snapshot);
+          clearImeCompositionFallbackTimer();
+          imeCompositionFallbackTimerRef.current = setTimeout(() => {
+              imeCompositionFallbackTimerRef.current = null;
+              if (editorRef.current !== editor) {
+                  return;
+              }
+              const currentValue = getEditorText();
+              if (currentValue !== snapshot.valueBefore) {
+                  syncQueryDraft(currentValue);
+                  return;
+              }
+
+              editor.executeEdits?.('gonavi-ime-composition-fallback', [{
+                  range: fallbackRange,
+                  text: committedText,
+                  forceMoveMarkers: true,
+              }]);
+              const nextValue = getEditorText();
+              syncQueryDraft(nextValue);
+
+              const model = editor.getModel?.();
+              const startOffset = Number(model?.getOffsetAt?.({
+                  lineNumber: fallbackRange.startLineNumber,
+                  column: fallbackRange.startColumn,
+              }));
+              const nextPosition = Number.isFinite(startOffset)
+                  ? normalizeEditorPosition(model?.getPositionAt?.(startOffset + committedText.length))
+                  : null;
+              if (nextPosition) {
+                  editor.setPosition?.(nextPosition);
+              }
+          }, 0);
+      };
       const handleEditorDragOver = (rawEvent: Event) => {
           const event = rawEvent as DragEvent;
           if (!hasSidebarSqlEditorDragPayload(event.dataTransfer)) return;
@@ -1432,6 +1551,9 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
       window.addEventListener('keydown', syncModifierState);
       window.addEventListener('keyup', syncModifierState);
       window.addEventListener('blur', handleWindowBlur);
+      editorDomNode?.addEventListener('beforeinput', handleImeBeforeInput, true);
+      editorDomNode?.addEventListener('compositionstart', handleImeCompositionStart, true);
+      editorDomNode?.addEventListener('compositionend', handleImeCompositionEnd, true);
       editorDomNode?.addEventListener('dragover', handleEditorDragOver, true);
       editorDomNode?.addEventListener('drop', handleEditorDrop, true);
 
@@ -1618,6 +1740,10 @@ const QueryEditor: React.FC<{ tab: TabData; isActive?: boolean }> = ({ tab, isAc
           window.removeEventListener('keydown', syncModifierState);
           window.removeEventListener('keyup', syncModifierState);
           window.removeEventListener('blur', handleWindowBlur);
+          clearImeCompositionFallbackTimer();
+          editorDomNode?.removeEventListener('beforeinput', handleImeBeforeInput, true);
+          editorDomNode?.removeEventListener('compositionstart', handleImeCompositionStart, true);
+          editorDomNode?.removeEventListener('compositionend', handleImeCompositionEnd, true);
           editorDomNode?.removeEventListener('dragover', handleEditorDragOver, true);
           editorDomNode?.removeEventListener('drop', handleEditorDrop, true);
       });
diff --git a/frontend/src/utils/aiChatSendShortcut.ts b/frontend/src/utils/aiChatSendShortcut.ts
index 496d139..894429d 100644
--- a/frontend/src/utils/aiChatSendShortcut.ts
+++ b/frontend/src/utils/aiChatSendShortcut.ts
@@ -1,4 +1,4 @@
-import { DEFAULT_SHORTCUT_OPTIONS, getShortcutDisplayLabel, isShortcutMatch, type ShortcutPlatform, type ShortcutPlatformBinding } from './shortcuts';
+import { DEFAULT_SHORTCUT_OPTIONS, getShortcutDisplayLabel, isImeComposingKeyEvent, isShortcutMatch, type ShortcutPlatform, type ShortcutPlatformBinding } from './shortcuts';
 
 export interface AIChatSendShortcutKeyEventLike {
   key?: string;
@@ -36,12 +36,7 @@ export const shouldSendAIChatOnKeyDown = (
   if (!binding?.enabled) {
     return false;
   }
-  // Some IMEs report Enter during an active candidate/composition as keyCode 229.
-  const isImeCandidateEvent = event.keyCode === 229
-    || event.which === 229
-    || event.nativeEvent?.keyCode === 229
-    || event.nativeEvent?.which === 229;
-  if (event.shiftKey || event.isComposing || event.nativeEvent?.isComposing || isImeCandidateEvent) {
+  if (event.shiftKey || isImeComposingKeyEvent(event as KeyboardEvent)) {
     return false;
   }
   return isShortcutMatch(event as KeyboardEvent, binding.combo);
diff --git a/frontend/src/utils/shortcuts.test.ts b/frontend/src/utils/shortcuts.test.ts
index ce01509..f7ce376 100644
--- a/frontend/src/utils/shortcuts.test.ts
+++ b/frontend/src/utils/shortcuts.test.ts
@@ -1,4 +1,4 @@
-import { beforeEach, describe, expect, it } from 'vitest';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
 
 import {
   setCurrentLanguage,
@@ -11,11 +11,17 @@ import {
   normalizeShortcutCombo,
   RESERVED_SHORTCUTS,
   comboToMonacoKeyBinding,
+  eventToShortcut,
   getPrimaryShortcutDisplayLabel,
   getShortcutDisplayLabel,
   getShortcutPrimaryModifierDisplayLabel,
+  installGlobalImeCompositionTracking,
+  isGlobalImeCompositionActive,
+  isImeComposingKeyEvent,
+  isShortcutMatch,
   resolveShortcutBinding,
   resolveShortcutDisplay,
+  setGlobalImeCompositionActive,
   sanitizeShortcutOptions,
   SHORTCUT_ACTION_META,
 } from './shortcuts';
@@ -23,6 +29,7 @@ import type { ConflictInfo } from './shortcuts';
 
 beforeEach(() => {
   setCurrentLanguage('zh-CN');
+  setGlobalImeCompositionActive(false);
 });
 
 // ─── findReservedConflict ────────────────────────────────────────────
@@ -164,6 +171,125 @@ describe('RESERVED_SHORTCUTS', () => {
   });
 });
 
+describe('IME shortcut guards', () => {
+  it('tracks composition state through global listeners', () => {
+    const windowListeners = new Map<string, EventListener[]>();
+    const documentListeners = new Map<string, EventListener[]>();
+    const target = {
+      addEventListener: vi.fn((type: string, listener: EventListener) => {
+        windowListeners.set(type, [...(windowListeners.get(type) || []), listener]);
+      }),
+      removeEventListener: vi.fn((type: string, listener: EventListener) => {
+        windowListeners.set(type, (windowListeners.get(type) || []).filter(item => item !== listener));
+      }),
+    };
+    const documentTarget = {
+      visibilityState: 'visible' as DocumentVisibilityState,
+      addEventListener: vi.fn((type: string, listener: EventListener) => {
+        documentListeners.set(type, [...(documentListeners.get(type) || []), listener]);
+      }),
+      removeEventListener: vi.fn((type: string, listener: EventListener) => {
+        documentListeners.set(type, (documentListeners.get(type) || []).filter(item => item !== listener));
+      }),
+    };
+
+    const dispose = installGlobalImeCompositionTracking(
+      target as unknown as Window,
+      documentTarget as unknown as Document,
+    );
+
+    windowListeners.get('compositionstart')?.forEach(listener => listener(new Event('compositionstart')));
+    expect(isGlobalImeCompositionActive()).toBe(true);
+
+    windowListeners.get('compositionend')?.forEach(listener => listener(new Event('compositionend')));
+    expect(isGlobalImeCompositionActive()).toBe(false);
+
+    windowListeners.get('compositionstart')?.forEach(listener => listener(new Event('compositionstart')));
+    windowListeners.get('blur')?.forEach(listener => listener(new Event('blur')));
+    expect(isGlobalImeCompositionActive()).toBe(false);
+
+    windowListeners.get('compositionstart')?.forEach(listener => listener(new Event('compositionstart')));
+    documentTarget.visibilityState = 'hidden';
+    documentListeners.get('visibilitychange')?.forEach(listener => listener(new Event('visibilitychange')));
+    expect(isGlobalImeCompositionActive()).toBe(false);
+
+    dispose();
+    expect(target.removeEventListener).toHaveBeenCalledWith('compositionstart', expect.any(Function), true);
+    expect(documentTarget.removeEventListener).toHaveBeenCalledWith('visibilitychange', expect.any(Function), true);
+  });
+
+  it('treats composing key events as non-shortcuts', () => {
+    const event = {
+      key: 'Process',
+      keyCode: 229,
+      which: 229,
+      isComposing: true,
+      ctrlKey: true,
+      metaKey: false,
+      altKey: false,
+      shiftKey: false,
+      nativeEvent: {
+        isComposing: true,
+        keyCode: 229,
+        which: 229,
+      },
+    } as unknown as KeyboardEvent;
+
+    expect(isImeComposingKeyEvent(event)).toBe(true);
+    expect(eventToShortcut(event)).toBe('');
+    expect(isShortcutMatch(event, 'Ctrl+Enter')).toBe(false);
+  });
+
+  it('treats number keys as non-shortcuts while a composition session is active', () => {
+    setGlobalImeCompositionActive(true);
+    const event = {
+      key: '1',
+      keyCode: 49,
+      which: 49,
+      ctrlKey: false,
+      metaKey: false,
+      altKey: false,
+      shiftKey: false,
+      isComposing: false,
+      nativeEvent: {
+        isComposing: false,
+      },
+    } as unknown as KeyboardEvent;
+
+    expect(isImeComposingKeyEvent(event)).toBe(true);
+    expect(eventToShortcut(event)).toBe('');
+    expect(isShortcutMatch(event, '1')).toBe(false);
+  });
+
+  it('treats Monaco visible IME textarea events as composing even without native flags', () => {
+    const target = {
+      className: 'inputarea monaco-mouse-cursor-text ime-input',
+      classList: {
+        contains: (name: string) => name === 'ime-input',
+      },
+      closest: vi.fn(),
+    } as unknown as EventTarget;
+    const event = {
+      key: '1',
+      keyCode: 49,
+      which: 49,
+      ctrlKey: false,
+      metaKey: false,
+      altKey: false,
+      shiftKey: false,
+      isComposing: false,
+      nativeEvent: {
+        isComposing: false,
+      },
+      target,
+    } as unknown as KeyboardEvent;
+
+    expect(isImeComposingKeyEvent(event)).toBe(true);
+    expect(eventToShortcut(event)).toBe('');
+    expect(isShortcutMatch(event, '1')).toBe(false);
+  });
+});
+
 // ─── shortcut defaults ───────────────────────────────────────────────
 
 describe('shortcut defaults', () => {
diff --git a/frontend/src/utils/shortcuts.ts b/frontend/src/utils/shortcuts.ts
index 2dc500d..8260c36 100644
--- a/frontend/src/utils/shortcuts.ts
+++ b/frontend/src/utils/shortcuts.ts
@@ -379,7 +379,106 @@ const normalizeKeyboardKey = (key: string): string => {
   return token.length > 1 ? token[0].toUpperCase() + token.slice(1) : token;
 };
 
+let globalImeCompositionActive = false;
+
+export const setGlobalImeCompositionActive = (active: boolean): void => {
+  globalImeCompositionActive = active === true;
+};
+
+export const isGlobalImeCompositionActive = (): boolean => globalImeCompositionActive;
+
+type ImeCompositionEventTarget = Pick<Window, 'addEventListener' | 'removeEventListener'>;
+type ImeCompositionDocumentTarget = Pick<Document, 'addEventListener' | 'removeEventListener'> & {
+  visibilityState?: DocumentVisibilityState;
+};
+
+export const installGlobalImeCompositionTracking = (
+  eventTarget: ImeCompositionEventTarget = window,
+  documentTarget: ImeCompositionDocumentTarget | null = document,
+): (() => void) => {
+  const handleCompositionStart = () => setGlobalImeCompositionActive(true);
+  const handleCompositionEnd = () => setGlobalImeCompositionActive(false);
+  const handleBlur = () => setGlobalImeCompositionActive(false);
+  const handleVisibilityChange = () => {
+    if (!documentTarget || documentTarget.visibilityState === 'hidden') {
+      setGlobalImeCompositionActive(false);
+    }
+  };
+
+  eventTarget.addEventListener('compositionstart', handleCompositionStart, true);
+  eventTarget.addEventListener('compositionend', handleCompositionEnd, true);
+  eventTarget.addEventListener('blur', handleBlur, true);
+  documentTarget?.addEventListener('visibilitychange', handleVisibilityChange, true);
+
+  return () => {
+    eventTarget.removeEventListener('compositionstart', handleCompositionStart, true);
+    eventTarget.removeEventListener('compositionend', handleCompositionEnd, true);
+    eventTarget.removeEventListener('blur', handleBlur, true);
+    documentTarget?.removeEventListener('visibilitychange', handleVisibilityChange, true);
+    setGlobalImeCompositionActive(false);
+  };
+};
+
+const isMonacoImeInputTarget = (target: EventTarget | null | undefined): boolean => {
+  if (!target || typeof target !== 'object') {
+    return false;
+  }
+
+  const element = target as Element & {
+    className?: unknown;
+    classList?: { contains?: (name: string) => boolean };
+    closest?: (selector: string) => Element | null;
+  };
+  if (typeof element.classList?.contains === 'function' && element.classList.contains('ime-input')) {
+    return true;
+  }
+  if (typeof element.className === 'string' && /\bime-input\b/.test(element.className)) {
+    return true;
+  }
+  if (typeof element.closest === 'function') {
+    return Boolean(element.closest('.monaco-editor .inputarea.ime-input, .monaco-editor textarea.ime-input, .ime-input'));
+  }
+  return false;
+};
+
+export const isImeComposingKeyEvent = (
+  event: (KeyboardEvent | ReactKeyboardEvent | null | undefined) & {
+    nativeEvent?: {
+      isComposing?: boolean;
+      keyCode?: number;
+      which?: number;
+    };
+    keyCode?: number;
+    which?: number;
+    isComposing?: boolean;
+    key?: string;
+    target?: EventTarget | null;
+  },
+): boolean => {
+  if (!event) {
+    return false;
+  }
+
+  const nativeEvent = event.nativeEvent;
+  const key = String(event.key || '').trim();
+  const keyCode = Number(event.keyCode ?? nativeEvent?.keyCode ?? 0);
+  const which = Number(event.which ?? nativeEvent?.which ?? 0);
+
+  return Boolean(
+    globalImeCompositionActive
+    || event.isComposing
+    || nativeEvent?.isComposing
+    || isMonacoImeInputTarget(event.target)
+    || key === 'Process'
+    || keyCode === 229
+    || which === 229,
+  );
+};
+
 export const eventToShortcut = (event: KeyboardEvent | ReactKeyboardEvent): string => {
+  if (isImeComposingKeyEvent(event)) {
+    return '';
+  }
   const key = normalizeKeyboardKey(event.key);
   if (!key || MODIFIER_SET.has(key as typeof MODIFIER_ORDER[number])) {
     return '';