diff --git a/extension/src/background.ts b/extension/src/background.ts
index 3fbf024..1a873cd 100644
--- a/extension/src/background.ts
+++ b/extension/src/background.ts
@@ -1,26 +1,10 @@
 import { RelayConnection, logger } from './relayConnection'
 import { createStore } from 'zustand/vanilla'
+import type { ExtensionState, ConnectionState, TabState, TabInfo } from './types'
 
 // Relay URL - fixed port for MCP bridge
 const RELAY_URL = 'ws://localhost:19988/extension'
 
-type ConnectionState = 'disconnected' | 'reconnecting' | 'connected' | 'error'
-type TabState = 'connecting' | 'connected' | 'error'
-
-interface TabInfo {
-  targetId: string
-  state: TabState
-  errorText?: string
-}
-
-interface ExtensionState {
-  connection: RelayConnection | undefined
-  connectedTabs: Map<number, TabInfo>
-  connectionState: ConnectionState
-  currentTabId: number | undefined
-  errorText: string | undefined
-}
-
 const useExtensionStore = createStore<ExtensionState>((set) => ({
   connection: undefined,
   connectedTabs: new Map(),
diff --git a/extension/src/types.ts b/extension/src/types.ts
new file mode 100644
index 0000000..6b46740
--- /dev/null
+++ b/extension/src/types.ts
@@ -0,0 +1,18 @@
+import type { RelayConnection } from './relayConnection'
+
+export type ConnectionState = 'disconnected' | 'reconnecting' | 'connected' | 'error'
+export type TabState = 'connecting' | 'connected' | 'error'
+
+export interface TabInfo {
+  targetId: string
+  state: TabState
+  errorText?: string
+}
+
+export interface ExtensionState {
+  connection: RelayConnection | undefined
+  connectedTabs: Map<number, TabInfo>
+  connectionState: ConnectionState
+  currentTabId: number | undefined
+  errorText: string | undefined
+}
diff --git a/playwriter/package.json b/playwriter/package.json
index 3f8503d..e9611b2 100644
--- a/playwriter/package.json
+++ b/playwriter/package.json
@@ -27,6 +27,7 @@
   "license": "",
   "devDependencies": {
     "@mizchi/selector-generator": "1.50.0-next",
+    "@types/chrome": "^0.0.315",
     "@types/node": "^24.10.1",
     "@vitest/ui": "^4.0.8",
     "mcp-extension": "workspace:*",
diff --git a/playwriter/src/mcp.test.ts b/playwriter/src/mcp.test.ts
index 5d65522..004cbed 100644
--- a/playwriter/src/mcp.test.ts
+++ b/playwriter/src/mcp.test.ts
@@ -55,7 +55,6 @@ declare global {
     var toggleExtensionForActiveTab: () => Promise<{ isConnected: boolean; state: ExtensionState }>;
     var getExtensionState: () => ExtensionState;
     var disconnectEverything: () => Promise<void>;
-    var chrome: any;
 }
 
 describe('MCP Server Tests', () => {
@@ -224,13 +223,12 @@ describe('MCP Server Tests', () => {
         // Get extension state to verify the page is marked as connected
         const extensionState = await serviceWorker.evaluate(async () => {
             const state = globalThis.getExtensionState()
-            const chrome = globalThis.chrome
             const tabs = await chrome.tabs.query({})
             const testTab = tabs.find((t: any) => t.url?.includes('mcp-test'))
             return {
-                connected: !!testTab && state.connectedTabs.has(testTab.id),
+                connected: !!testTab && !!testTab.id && state.connectedTabs.has(testTab.id),
                 tabId: testTab?.id,
-                tabInfo: testTab ? state.connectedTabs.get(testTab.id) : null,
+                tabInfo: testTab?.id ? state.connectedTabs.get(testTab.id) : null,
                 connectionState: state.connectionState
             }
         })
@@ -583,8 +581,8 @@ describe('MCP Server Tests', () => {
              const tabA = tabs.find((t: any) => t.url?.includes('tab-a'))
              const tabB = tabs.find((t: any) => t.url?.includes('tab-b'))
              return {
-                 idA: state.connectedTabs.get(tabA?.id)?.targetId,
-                 idB: state.connectedTabs.get(tabB?.id)?.targetId
+                 idA: state.connectedTabs.get(tabA?.id ?? -1)?.targetId,
+                 idB: state.connectedTabs.get(tabB?.id ?? -1)?.targetId
              }
         })
 
@@ -669,8 +667,8 @@ describe('MCP Server Tests', () => {
              const tabA = tabs.find((t: any) => t.url?.includes('tab-a'))
              const tabB = tabs.find((t: any) => t.url?.includes('tab-b'))
              return {
-                 idA: state.connectedTabs.get(tabA?.id)?.targetId,
-                 idB: state.connectedTabs.get(tabB?.id)?.targetId
+                 idA: state.connectedTabs.get(tabA?.id ?? -1)?.targetId,
+                 idB: state.connectedTabs.get(tabB?.id ?? -1)?.targetId
              }
         })
 
diff --git a/playwriter/tsconfig.json b/playwriter/tsconfig.json
index c17b043..1bb3589 100644
--- a/playwriter/tsconfig.json
+++ b/playwriter/tsconfig.json
@@ -2,7 +2,8 @@
   "extends": "../tsconfig.base.json",
   "compilerOptions": {
     "rootDir": "src",
-    "outDir": "dist"
+    "outDir": "dist",
+    "types": ["node", "chrome"]
   },
   "include": ["src"]
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 8f37e75..4b9421a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -94,6 +94,9 @@ importers:
       '@mizchi/selector-generator':
         specifier: 1.50.0-next
         version: 1.50.0-next
+      '@types/chrome':
+        specifier: ^0.0.315
+        version: 0.0.315
       '@types/node':
         specifier: ^24.10.1
         version: 24.10.1