diff --git a/src/preload/index.ts b/src/preload/index.ts
new file mode 100644
index 0000000..7024fc6
--- /dev/null
+++ b/src/preload/index.ts
@@ -0,0 +1,27 @@
+import { contextBridge, ipcRenderer } from 'electron';
+import type { InklingApi, Note } from '@shared/types';
+
+const api: InklingApi = {
+  capture: {
+    submit: (payload) => ipcRenderer.invoke('capture:submit', payload),
+    hide: () => ipcRenderer.send('capture:hide')
+  },
+  inbox: {
+    listNotes: (opts) => ipcRenderer.invoke('inbox:list', opts),
+    updateAiFields: (noteId, fields) =>
+      ipcRenderer.invoke('inbox:updateAi', { noteId, fields }),
+    deleteNote: (noteId) => ipcRenderer.invoke('inbox:delete', noteId),
+    setIntent: (noteId, text) => ipcRenderer.invoke('inbox:setIntent', { noteId, text }),
+    dismissIntent: (noteId) => ipcRenderer.invoke('inbox:dismissIntent', noteId),
+    getContinuity: () => ipcRenderer.invoke('inbox:continuity'),
+    getPendingCount: () => ipcRenderer.invoke('inbox:pendingCount'),
+    getOllamaStatus: () => ipcRenderer.invoke('inbox:ollamaStatus'),
+    onNoteUpdated: (cb) => {
+      const listener = (_e: unknown, note: Note) => cb(note);
+      ipcRenderer.on('note:updated', listener);
+      return () => ipcRenderer.off('note:updated', listener);
+    }
+  }
+};
+
+contextBridge.exposeInMainWorld('inkling', api);
diff --git a/src/shared/types.ts b/src/shared/types.ts
index 431d541..3029e63 100644
--- a/src/shared/types.ts
+++ b/src/shared/types.ts
@@ -1,6 +1,74 @@
 declare global {
-  namespace Electron {
-    interface App { isQuitting?: boolean; }
-  }
+  namespace Electron { interface App { isQuitting?: boolean; } }
+  interface Window { inkling: InklingApi; }
 }
+
+export interface NoteMedia {
+  id: string;
+  kind: 'image';
+  relPath: string;
+  mime: string;
+  bytes: number;
+}
+
+export type AiStatus = 'pending' | 'done' | 'failed';
+
+export interface NoteTag {
+  name: string;
+  source: 'ai' | 'user';
+}
+
+export interface Note {
+  id: string;
+  rawText: string;
+  aiTitle: string | null;
+  aiSummary: string | null;
+  aiStatus: AiStatus;
+  aiError: string | null;
+  aiProvider: string | null;
+  aiGeneratedAt: string | null;
+  titleEditedByUser: boolean;
+  summaryEditedByUser: boolean;
+  userIntent: string | null;
+  intentPromptedAt: string | null;
+  createdAt: string;
+  updatedAt: string;
+  tags: NoteTag[];
+  media: NoteMedia[];
+}
+
+export interface WeeklyContinuity {
+  weekStart: string;                 // ISO date (KST 월요일)
+  weekCount: number;
+  weekTarget: number;                // 7
+  consecutiveCompleteWeeks: number;
+  showRecoveryToast: boolean;
+  lastNoteAt: string | null;
+}
+
+export interface CaptureApi {
+  submit(payload: { text: string; images: ArrayBuffer[] }): Promise<{ noteId: string }>;
+  hide(): void;
+}
+
+export interface InboxApi {
+  listNotes(opts: { limit: number; cursor?: string }): Promise<Note[]>;
+  updateAiFields(
+    noteId: string,
+    fields: { title?: string; summary?: string; tags?: string[] }
+  ): Promise<void>;
+  deleteNote(noteId: string): Promise<void>;
+  setIntent(noteId: string, text: string): Promise<void>;
+  dismissIntent(noteId: string): Promise<void>;
+  getContinuity(): Promise<WeeklyContinuity>;
+  getPendingCount(): Promise<number>;
+  getOllamaStatus(): Promise<{ ok: boolean; reason?: string }>;
+  onNoteUpdated(cb: (note: Note) => void): () => void;
+}
+
+export interface InklingApi {
+  capture: CaptureApi;
+  inbox: InboxApi;
+}
+
 export {};