diff --git a/packages/shared/package.json b/packages/shared/package.json
new file mode 100644
index 0000000..dc8b00d
--- /dev/null
+++ b/packages/shared/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "@droidclaw/shared",
+  "version": "0.0.1",
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "scripts": {
+    "typecheck": "tsc --noEmit"
+  },
+  "devDependencies": {
+    "typescript": "^5.9.2"
+  }
+}
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
new file mode 100644
index 0000000..aeea426
--- /dev/null
+++ b/packages/shared/src/index.ts
@@ -0,0 +1,2 @@
+export * from "./types.js";
+export * from "./protocol.js";
diff --git a/packages/shared/src/protocol.ts b/packages/shared/src/protocol.ts
new file mode 100644
index 0000000..420cd56
--- /dev/null
+++ b/packages/shared/src/protocol.ts
@@ -0,0 +1,41 @@
+import type { UIElement, DeviceInfo } from "./types.js";
+
+export type DeviceMessage =
+  | { type: "auth"; apiKey: string; deviceInfo?: DeviceInfo }
+  | { type: "screen"; requestId: string; elements: UIElement[]; screenshot?: string; packageName?: string }
+  | { type: "result"; requestId: string; success: boolean; error?: string; data?: string }
+  | { type: "goal"; text: string }
+  | { type: "pong" };
+
+export type ServerToDeviceMessage =
+  | { type: "auth_ok"; deviceId: string }
+  | { type: "auth_error"; message: string }
+  | { type: "get_screen"; requestId: string }
+  | { type: "tap"; requestId: string; x: number; y: number }
+  | { type: "type"; requestId: string; text: string }
+  | { type: "swipe"; requestId: string; x1: number; y1: number; x2: number; y2: number; duration?: number }
+  | { type: "enter"; requestId: string }
+  | { type: "back"; requestId: string }
+  | { type: "home"; requestId: string }
+  | { type: "longpress"; requestId: string; x: number; y: number }
+  | { type: "launch"; requestId: string; packageName: string }
+  | { type: "clear"; requestId: string }
+  | { type: "clipboard_set"; requestId: string; text: string }
+  | { type: "clipboard_get"; requestId: string }
+  | { type: "paste"; requestId: string }
+  | { type: "open_url"; requestId: string; url: string }
+  | { type: "switch_app"; requestId: string; packageName: string }
+  | { type: "notifications"; requestId: string }
+  | { type: "keyevent"; requestId: string; code: number }
+  | { type: "open_settings"; requestId: string }
+  | { type: "wait"; requestId: string; duration?: number }
+  | { type: "ping" }
+  | { type: "goal_started"; sessionId: string; goal: string }
+  | { type: "goal_completed"; sessionId: string; success: boolean; stepsUsed: number };
+
+export type DashboardMessage =
+  | { type: "device_online"; deviceId: string; name: string }
+  | { type: "device_offline"; deviceId: string }
+  | { type: "step"; sessionId: string; step: number; action: Record<string, unknown>; reasoning: string; screenHash: string }
+  | { type: "goal_started"; sessionId: string; goal: string; deviceId: string }
+  | { type: "goal_completed"; sessionId: string; success: boolean; stepsUsed: number };
diff --git a/packages/shared/src/types.ts b/packages/shared/src/types.ts
new file mode 100644
index 0000000..11b7863
--- /dev/null
+++ b/packages/shared/src/types.ts
@@ -0,0 +1,66 @@
+export interface UIElement {
+  id: string;
+  text: string;
+  type: string;
+  bounds: string;
+  center: [number, number];
+  size: [number, number];
+  clickable: boolean;
+  editable: boolean;
+  enabled: boolean;
+  checked: boolean;
+  focused: boolean;
+  selected: boolean;
+  scrollable: boolean;
+  longClickable: boolean;
+  password: boolean;
+  hint: string;
+  action: "tap" | "type" | "longpress" | "scroll" | "read";
+  parent: string;
+  depth: number;
+}
+
+export interface ActionDecision {
+  action: string;
+  coordinates?: [number, number];
+  text?: string;
+  direction?: string;
+  reason?: string;
+  package?: string;
+  activity?: string;
+  uri?: string;
+  extras?: Record<string, string>;
+  command?: string;
+  filename?: string;
+  think?: string;
+  plan?: string[];
+  planProgress?: string;
+  skill?: string;
+  query?: string;
+  url?: string;
+  path?: string;
+  source?: string;
+  dest?: string;
+  code?: number;
+  setting?: string;
+}
+
+export interface ActionResult {
+  success: boolean;
+  message: string;
+  data?: string;
+}
+
+export interface DeviceInfo {
+  model: string;
+  androidVersion: string;
+  screenWidth: number;
+  screenHeight: number;
+}
+
+export interface ScreenState {
+  elements: UIElement[];
+  screenshot?: string;
+  packageName?: string;
+  fallbackReason?: string;
+}
diff --git a/packages/shared/tsconfig.json b/packages/shared/tsconfig.json
new file mode 100644
index 0000000..582e96c
--- /dev/null
+++ b/packages/shared/tsconfig.json
@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ES2022",
+    "moduleResolution": "bundler",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "declaration": true,
+    "outDir": "dist",
+    "rootDir": "src"
+  },
+  "include": ["src/**/*.ts"]
+}