AndurilCode · gabrypavanello · Jan 14, 2026 · Jan 13, 2026 · Jan 13, 2026 · Jan 13, 2026
diff --git a/examples/minimal/package.json b/examples/minimal/package.json
@@ -22,7 +22,7 @@
     "@mcp-apps-kit/ui-react-builder": "workspace:*",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
-    "zod": "^4.0.0"
+    "zod": "^4.3.5"
   },
   "devDependencies": {
     "@mcp-apps-kit/testing": "workspace:*",

diff --git a/examples/restaurant-finder/package.json b/examples/restaurant-finder/package.json
@@ -19,7 +19,7 @@
     "@mcp-apps-kit/ui-react": "workspace:*",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
-    "zod": "^4.0.0"
+    "zod": "^4.3.5"
   },
   "devDependencies": {
     "@types/node": "^25.0.7",

diff --git a/examples/weather-app/package.json b/examples/weather-app/package.json
@@ -21,7 +21,7 @@
     "@mcp-apps-kit/ui-react": "workspace:*",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
-    "zod": "^4.0.0"
+    "zod": "^4.3.5"
   },
   "devDependencies": {
     "@mcp-apps-kit/testing": "workspace:*",

diff --git a/examples/weather-app/server/index.ts b/examples/weather-app/server/index.ts
@@ -115,7 +115,7 @@ const app = createApp({
   version: "0.1.0",
 
   config: {
-    protocol: "openai",
+    protocol: "mcp",
   },
 
   tools: {

diff --git a/packages/core/package.json b/packages/core/package.json
@@ -42,18 +42,18 @@
     "directory": "packages/core"
   },
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.25.1",
+    "@modelcontextprotocol/sdk": "^1.25.2",
     "express": "^5.1.0",
     "jsonwebtoken": "^9.0.3",
     "jwks-rsa": "^3.2.0",
-    "zod": "^4.0.0"
+    "zod": "^4.3.5"
   },
   "devDependencies": {
     "@types/express": "^5.0.0",
     "@types/jsonwebtoken": "^9.0.7"
   },
   "peerDependencies": {
-    "zod": "^4.0.0"
+    "zod": "^4.3.5"
   },
   "engines": {
     "node": ">=18.0.0"

diff --git a/packages/testing/package.json b/packages/testing/package.json
@@ -61,9 +61,9 @@
     "directory": "packages/testing"
   },
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.25.1",
+    "@modelcontextprotocol/sdk": "^1.25.2",
     "debug": "^4.0.0",
-    "zod": "^4.0.0"
+    "zod": "^4.3.5"
   },
   "peerDependencies": {
     "@anthropic-ai/sdk": ">=0.30.0",

diff --git a/packages/ui-react-builder/package.json b/packages/ui-react-builder/package.json
@@ -54,10 +54,6 @@
     "url": "git+https://github.com/AndurilCode/mcp-apps-kit.git",
     "directory": "packages/ui-react-builder"
   },
-  "dependencies": {
-    "@typescript-eslint/typescript-estree": "^8.0.0",
-    "esbuild": "^0.25.0"
-  },
   "peerDependencies": {
     "@mcp-apps-kit/core": "^0.4.0",
     "@mcp-apps-kit/ui-react": "^0.4.0",
@@ -70,12 +66,16 @@
       "optional": true
     }
   },
+  "dependencies": {
+    "@typescript-eslint/types": "^8.53.0",
+    "@typescript-eslint/typescript-estree": "^8.53.0",
+    "esbuild": "^0.27.2"
+  },
   "devDependencies": {
     "@mcp-apps-kit/core": "workspace:*",
     "@mcp-apps-kit/ui-react": "workspace:*",
     "@types/react": "^19.2.8",
     "@types/react-dom": "^19.2.3",
-    "@typescript-eslint/types": "^8.53.0",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
     "vite": "^7.3.1"

diff --git a/packages/ui-react-builder/tsup.config.ts b/packages/ui-react-builder/tsup.config.ts
@@ -12,13 +12,20 @@ export default defineConfig({
   clean: true,
   treeshake: true,
   minify: true,
+  // External dependencies - these must be listed in package.json dependencies (not devDependencies)
+  // because they're needed at runtime:
+  // - @typescript-eslint/* packages: Used by ast-parser.ts to parse user TypeScript code at build time
+  // - esbuild: Used to bundle React components into standalone HTML files
+  // - vite: Peer dependency, used when plugin is loaded by Vite config
   external: [
     "react",
     "react-dom",
     "@mcp-apps-kit/core",
     "@mcp-apps-kit/ui-react",
     "esbuild",
     "vite",
+    "@typescript-eslint/typescript-estree",
+    "@typescript-eslint/types",
   ],
   esbuildOptions(options) {
     options.jsx = "automatic";

diff --git a/packages/ui-react/src/hooks.ts b/packages/ui-react/src/hooks.ts
@@ -14,6 +14,7 @@ import type {
   ModalResult,
   HostCapabilities,
   HostVersion,
+  UpdateModelContextParams,
 } from "@mcp-apps-kit/ui";
 import { clientDebugLogger, type ClientDebugLogger } from "@mcp-apps-kit/ui";
 import { useAppsContext } from "./context";
@@ -250,6 +251,62 @@ export function useWidgetState<S>(defaultValue: S): [S, (newState: S | ((prev: S
   return [state, setState];
 }
 
+// =============================================================================
+// MODEL CONTEXT HOOKS
+// =============================================================================
+
+/**
+ * Hook to update the host's model context
+ *
+ * Unlike sendMessage which triggers follow-up actions, context updates
+ * inform the model about app state without triggering responses.
+ *
+ * Platform implementation details:
+ * - MCP Apps: Uses native protocol feature for pure context updates
+ * - ChatGPT: Uses setState/setWidgetState internally (exposes to AI + persists)
+ *
+ * On ChatGPT, both setState() and updateModelContext() expose state to the
+ * AI model. Use setState() for persistence-focused use cases, and
+ * updateModelContext() for context-focused use cases.
+ *
+ * @returns Function to update model context
+ *
+ * @example
+ * ```tsx
+ * function ShoppingCart({ items }) {
+ *   const updateContext = useUpdateModelContext();
+ *
+ *   // Keep the model informed about cart state
+ *   useEffect(() => {
+ *     updateContext({
+ *       structuredContent: {
+ *         itemCount: items.length,
+ *         total: calculateTotal(items),
+ *         currency: "USD"
+ *       }
+ *     });
+ *   }, [items, updateContext]);
+ *
+ *   return <CartUI items={items} />;
+ * }
+ * ```
+ */
+export function useUpdateModelContext(): (params: UpdateModelContextParams) => Promise<void> {
+  const { client } = useAppsContext();
+
+  return useCallback(
+    async (params: UpdateModelContextParams) => {
+      if (!client) {
+        // eslint-disable-next-line no-console
+        console.warn("[useUpdateModelContext] Client not available");
+        return;
+      }
+      await client.updateModelContext(params);
+    },
+    [client]
+  );
+}
+
 // =============================================================================
 // UTILITY HOOKS
 // =============================================================================

diff --git a/packages/ui-react/src/index.ts b/packages/ui-react/src/index.ts
@@ -17,6 +17,10 @@ export type {
   AppToolDefinition,
   CallToolHandler,
   ListToolsHandler,
+  // Model context types (ext-apps v0.4.0+)
+  ContainerDimensions,
+  ContentBlock,
+  UpdateModelContextParams,
 } from "@mcp-apps-kit/ui";
 
 // Context
@@ -51,6 +55,8 @@ export {
   useHostCapabilities,
   useHostVersion,
   useSizeChangedNotifications,
+  // Model context (ext-apps v0.4.0+)
+  useUpdateModelContext,
 } from "./hooks";
 
 // File operation types

diff --git a/packages/ui/package.json b/packages/ui/package.json
@@ -44,7 +44,7 @@
     "directory": "packages/ui"
   },
   "dependencies": {
-    "@modelcontextprotocol/ext-apps": "^0.2.2"
+    "@modelcontextprotocol/ext-apps": "^0.4.0"
   },
   "engines": {
     "node": ">=18.0.0"