chore: version packages (#186)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

.changeset/config.json

@@ -17,7 +17,9 @@
       "@json-render/jotai",
       "@json-render/vue",
       "@json-render/xstate",
-      "@json-render/image"
+      "@json-render/image",
+      "@json-render/mcp",
+      "@json-render/svelte"
     ]
   ],
   "linked": [],

.cursor/mcp.json

@@ -0,0 +1,8 @@
+{
+  "mcpServers": {
+    "json-render": {
+      "command": "npx",
+      "args": ["tsx", "examples/mcp/server.ts", "--stdio"]
+    }
+  }
+}

.vscode/mcp.json

@@ -0,0 +1,9 @@
+{
+  "servers": {
+    "json-render": {
+      "type": "stdio",
+      "command": "npx",
+      "args": ["tsx", "examples/mcp/server.ts", "--stdio"]
+    }
+  }
+}

README.md

@@ -19,6 +19,8 @@ npm install @json-render/core @json-render/react-pdf
 npm install @json-render/core @json-render/react-email @react-email/components @react-email/render
 # or for Vue
 npm install @json-render/core @json-render/vue
+# or for Svelte
+npm install @json-render/core @json-render/svelte
 ```
 
 ## Why json-render?
@@ -28,7 +30,7 @@ json-render is a **Generative UI** framework: AI generates interfaces from natur
 - **Guardrailed** - AI can only use components in your catalog
 - **Predictable** - JSON output matches your schema, every time
 - **Fast** - Stream and render progressively as the model responds
-- **Cross-Platform** - React, Vue (web), React Native (mobile) from the same catalog
+- **Cross-Platform** - React, Vue, Svelte (web), React Native (mobile) from the same catalog
 - **Batteries Included** - 36 pre-built shadcn/ui components ready to use
 
 ## Quick Start
@@ -116,16 +118,19 @@ function Dashboard({ spec }) {
 | `@json-render/core` | Schemas, catalogs, AI prompts, dynamic props, SpecStream utilities |
 | `@json-render/react` | React renderer, contexts, hooks |
 | `@json-render/vue` | Vue 3 renderer, composables, providers |
+| `@json-render/svelte` | Svelte 5 renderer with runes-based reactivity |
 | `@json-render/shadcn` | 36 pre-built shadcn/ui components (Radix UI + Tailwind CSS) |
 | `@json-render/react-native` | React Native renderer with standard mobile components |
 | `@json-render/remotion` | Remotion video renderer, timeline schema |
 | `@json-render/react-pdf` | React PDF renderer for generating PDF documents from specs |
 | `@json-render/react-email` | React Email renderer for HTML/plain-text emails from specs |
 | `@json-render/image` | Image renderer for SVG/PNG output (OG images, social cards) via Satori |
+| `@json-render/codegen` | Utilities for generating code from json-render UI trees |
 | `@json-render/redux` | Redux / Redux Toolkit adapter for `StateStore` |
 | `@json-render/zustand` | Zustand adapter for `StateStore` |
 | `@json-render/jotai` | Jotai adapter for `StateStore` |
 | `@json-render/xstate` | XState Store (atom) adapter for `StateStore` |
+| `@json-render/mcp` | MCP Apps integration for Claude, ChatGPT, Cursor, VS Code |
 
 ## Renderers
 
@@ -177,6 +182,23 @@ const { registry } = defineRegistry(catalog, {
 // <Renderer :spec="spec" :registry="registry" />
 ```
 
+### Svelte (UI)
+
+```typescript
+import { defineRegistry, Renderer } from "@json-render/svelte";
+import { schema } from "@json-render/svelte/schema";
+
+const { registry } = defineRegistry(catalog, {
+  components: {
+    Card: ({ props, children }) => /* Svelte 5 snippet */,
+    Button: ({ props, emit }) => /* Svelte 5 snippet */,
+  },
+});
+
+// In your Svelte component:
+// <Renderer spec={spec} registry={registry} />
+```
+
 ### shadcn/ui (Web)
 
 ```tsx

apps/web/CHANGELOG.md

@@ -1,5 +1,14 @@
 # web
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/codegen@0.12.0
+  - @json-render/react@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

apps/web/app/(main)/docs/api/jotai/page.mdx

@@ -0,0 +1,104 @@
+import { pageMetadata } from "@/lib/page-metadata"
+export const metadata = pageMetadata("docs/api/jotai")
+
+# @json-render/jotai
+
+Jotai adapter for json-render's `StateStore` interface.
+
+## Installation
+
+```bash
+npm install @json-render/jotai @json-render/core @json-render/react jotai
+```
+
+## jotaiStateStore
+
+Create a `StateStore` backed by a Jotai atom.
+
+```typescript
+import { jotaiStateStore } from "@json-render/jotai";
+```
+
+### Options
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Required</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>atom</code></td>
+      <td><code>{'WritableAtom<StateModel, [StateModel], void>'}</code></td>
+      <td>Yes</td>
+      <td>A writable atom holding the state model.</td>
+    </tr>
+    <tr>
+      <td><code>store</code></td>
+      <td>Jotai <code>Store</code></td>
+      <td>No</td>
+      <td>The Jotai store instance. Defaults to a new store created internally. Pass your own to share state with <code>{'<Provider>'}</code>.</td>
+    </tr>
+  </tbody>
+</table>
+
+### Example
+
+```typescript
+import { atom } from "jotai";
+import { jotaiStateStore } from "@json-render/jotai";
+import { StateProvider } from "@json-render/react";
+
+const uiAtom = atom<Record<string, unknown>>({ count: 0 });
+const store = jotaiStateStore({ atom: uiAtom });
+```
+
+```tsx
+<StateProvider store={store}>
+  {/* json-render reads/writes go through Jotai */}
+</StateProvider>
+```
+
+### Shared Jotai Store
+
+If your app already uses a Jotai `<Provider>` with a custom store, pass it so both json-render and your components share the same state:
+
+```typescript
+import { atom, createStore } from "jotai";
+import { Provider as JotaiProvider } from "jotai/react";
+import { jotaiStateStore } from "@json-render/jotai";
+import { StateProvider } from "@json-render/react";
+
+const jStore = createStore();
+const uiAtom = atom<Record<string, unknown>>({ count: 0 });
+const store = jotaiStateStore({ atom: uiAtom, store: jStore });
+```
+
+```tsx
+<JotaiProvider store={jStore}>
+  <StateProvider store={store}>
+    {/* Both json-render and useAtom() see the same state */}
+  </StateProvider>
+</JotaiProvider>
+```
+
+## Re-exports
+
+<table>
+  <thead>
+    <tr>
+      <th>Export</th>
+      <th>Source</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>StateStore</code></td>
+      <td><code>@json-render/core</code></td>
+    </tr>
+  </tbody>
+</table>

apps/web/app/(main)/docs/api/mcp/page.mdx

@@ -0,0 +1,247 @@
+import { pageMetadata } from "@/lib/page-metadata"
+export const metadata = pageMetadata("docs/api/mcp")
+
+# @json-render/mcp
+
+MCP Apps integration for json-render. Serve json-render UIs as interactive [MCP Apps](https://modelcontextprotocol.io/docs/extensions/apps) inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients.
+
+## Install
+
+```bash
+npm install @json-render/mcp @json-render/core @modelcontextprotocol/sdk
+```
+
+For the iframe-side React UI, also install:
+
+```bash
+npm install @json-render/react react react-dom
+```
+
+See the [MCP example](https://github.com/vercel-labs/json-render/tree/main/examples/mcp) for a full working example.
+
+## Overview
+
+MCP Apps let MCP servers return interactive HTML UIs that render directly inside chat conversations. `@json-render/mcp` bridges json-render catalogs with the MCP Apps protocol:
+
+1. Your **catalog** defines which components and actions the AI can use
+2. The **MCP server** exposes the catalog as a tool with the spec schema
+3. The **bundled HTML** renders json-render specs inside the host's sandboxed iframe
+4. The AI generates a spec, the host renders it, and users interact with the live UI
+
+## Server API
+
+### createMcpApp
+
+Create a fully-configured MCP server. This is the main entry point.
+
+```typescript
+import { createMcpApp } from "@json-render/mcp";
+import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+import fs from "node:fs";
+
+const server = createMcpApp({
+  name: "My Dashboard",
+  version: "1.0.0",
+  catalog: myCatalog,
+  html: fs.readFileSync("dist/index.html", "utf-8"),
+});
+
+await server.connect(new StdioServerTransport());
+```
+
+#### CreateMcpAppOptions
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>name</code></td>
+      <td><code>string</code></td>
+      <td>Server name shown in client UIs</td>
+    </tr>
+    <tr>
+      <td><code>version</code></td>
+      <td><code>string</code></td>
+      <td>Server version</td>
+    </tr>
+    <tr>
+      <td><code>catalog</code></td>
+      <td><code>Catalog</code></td>
+      <td>json-render catalog defining available components</td>
+    </tr>
+    <tr>
+      <td><code>html</code></td>
+      <td><code>string</code></td>
+      <td>Self-contained HTML for the iframe UI</td>
+    </tr>
+    <tr>
+      <td><code>tool</code></td>
+      <td><code>McpToolOptions</code></td>
+      <td>Optional tool name/title/description overrides</td>
+    </tr>
+  </tbody>
+</table>
+
+### registerJsonRenderTool
+
+Register a json-render tool on an existing `McpServer`. Use this when you need to add json-render to a server that has other tools.
+
+```typescript
+import { registerJsonRenderTool } from "@json-render/mcp";
+
+registerJsonRenderTool(server, {
+  catalog,
+  name: "render-ui",
+  title: "Render UI",
+  description: "Render an interactive UI",
+  resourceUri: "ui://render-ui/view.html",
+});
+```
+
+### registerJsonRenderResource
+
+Register the UI resource that serves the bundled HTML.
+
+```typescript
+import { registerJsonRenderResource } from "@json-render/mcp";
+
+registerJsonRenderResource(server, {
+  resourceUri: "ui://render-ui/view.html",
+  html: bundledHtml,
+});
+```
+
+## Client API (`@json-render/mcp/app`)
+
+These exports run inside the sandboxed iframe rendered by the MCP host.
+
+### useJsonRenderApp
+
+React hook that connects to the MCP host, listens for tool results, and maintains the current json-render spec.
+
+```tsx
+import { useJsonRenderApp } from "@json-render/mcp/app";
+import { JSONUIProvider, Renderer } from "@json-render/react";
+
+function McpAppView({ registry }) {
+  const { spec, loading, connected, error } = useJsonRenderApp({
+    name: "my-app",
+    version: "1.0.0",
+  });
+
+  if (error) return <div>Error: {error.message}</div>;
+  if (!spec) return <div>Waiting...</div>;
+
+  return (
+    <JSONUIProvider registry={registry} initialState={spec.state ?? {}}>
+      <Renderer spec={spec} registry={registry} loading={loading} />
+    </JSONUIProvider>
+  );
+}
+```
+
+#### UseJsonRenderAppReturn
+
+<table>
+  <thead>
+    <tr>
+      <th>Field</th>
+      <th>Type</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>spec</code></td>
+      <td><code>{'Spec | null'}</code></td>
+      <td>Current json-render spec</td>
+    </tr>
+    <tr>
+      <td><code>loading</code></td>
+      <td><code>boolean</code></td>
+      <td>Whether the spec is still being received</td>
+    </tr>
+    <tr>
+      <td><code>connected</code></td>
+      <td><code>boolean</code></td>
+      <td>Whether connected to the host</td>
+    </tr>
+    <tr>
+      <td><code>connecting</code></td>
+      <td><code>boolean</code></td>
+      <td>Whether currently connecting</td>
+    </tr>
+    <tr>
+      <td><code>error</code></td>
+      <td><code>{'Error | null'}</code></td>
+      <td>Connection error, if any</td>
+    </tr>
+    <tr>
+      <td><code>app</code></td>
+      <td><code>{'App | null'}</code></td>
+      <td>The underlying MCP App instance</td>
+    </tr>
+    <tr>
+      <td><code>callServerTool</code></td>
+      <td><code>{'(name, args?) => Promise<void>'}</code></td>
+      <td>Call an MCP server tool and update spec from result</td>
+    </tr>
+  </tbody>
+</table>
+
+### buildAppHtml
+
+Generate a self-contained HTML page from bundled JavaScript and CSS.
+
+```typescript
+import { buildAppHtml } from "@json-render/mcp/app";
+import fs from "node:fs";
+
+const html = buildAppHtml({
+  title: "Dashboard",
+  js: fs.readFileSync("dist/app.js", "utf-8"),
+  css: fs.readFileSync("dist/app.css", "utf-8"),
+});
+```
+
+## Client Configuration
+
+### Cursor
+
+Add to `.cursor/mcp.json`:
+
+```json
+{
+  "mcpServers": {
+    "json-render": {
+      "command": "npx",
+      "args": ["tsx", "path/to/server.ts", "--stdio"]
+    }
+  }
+}
+```
+
+### Claude Desktop
+
+Add to `~/Library/Application Support/Claude/claude_desktop_config.json`:
+
+```json
+{
+  "mcpServers": {
+    "json-render": {
+      "command": "npx",
+      "args": ["tsx", "/absolute/path/to/server.ts", "--stdio"]
+    }
+  }
+}
+```
+
+## Supported Clients
+
+MCP Apps are supported by Claude (web and desktop), ChatGPT, VS Code (GitHub Copilot), Cursor, Goose, and Postman.

apps/web/app/(main)/docs/api/redux/page.mdx

@@ -0,0 +1,104 @@
+import { pageMetadata } from "@/lib/page-metadata"
+export const metadata = pageMetadata("docs/api/redux")
+
+# @json-render/redux
+
+Redux / Redux Toolkit adapter for json-render's `StateStore` interface.
+
+## Installation
+
+```bash
+npm install @json-render/redux @json-render/core @json-render/react redux
+# or with Redux Toolkit (recommended):
+npm install @json-render/redux @json-render/core @json-render/react @reduxjs/toolkit
+```
+
+## reduxStateStore
+
+Create a `StateStore` backed by a Redux store.
+
+```typescript
+import { reduxStateStore } from "@json-render/redux";
+```
+
+### Options
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Required</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>store</code></td>
+      <td><code>Store</code></td>
+      <td>Yes</td>
+      <td>The Redux store instance.</td>
+    </tr>
+    <tr>
+      <td><code>selector</code></td>
+      <td><code>{'(state: S) => StateModel'}</code></td>
+      <td>No</td>
+      <td>Select the json-render slice from the Redux state tree. Defaults to <code>{'(state) => state'}</code>.</td>
+    </tr>
+    <tr>
+      <td><code>dispatch</code></td>
+      <td><code>{'(nextState: StateModel, store: Store) => void'}</code></td>
+      <td>Yes</td>
+      <td>Dispatch an action that replaces the selected slice with the next state.</td>
+    </tr>
+  </tbody>
+</table>
+
+### Example
+
+```typescript
+import { configureStore, createSlice } from "@reduxjs/toolkit";
+import { reduxStateStore } from "@json-render/redux";
+import { StateProvider } from "@json-render/react";
+
+const uiSlice = createSlice({
+  name: "ui",
+  initialState: { count: 0 } as Record<string, unknown>,
+  reducers: {
+    replaceUiState: (_state, action) => action.payload,
+  },
+});
+
+const reduxStore = configureStore({
+  reducer: { ui: uiSlice.reducer },
+});
+
+const store = reduxStateStore({
+  store: reduxStore,
+  selector: (state) => state.ui,
+  dispatch: (next, s) => s.dispatch(uiSlice.actions.replaceUiState(next)),
+});
+```
+
+```tsx
+<StateProvider store={store}>
+  {/* json-render reads/writes go through Redux */}
+</StateProvider>
+```
+
+## Re-exports
+
+<table>
+  <thead>
+    <tr>
+      <th>Export</th>
+      <th>Source</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>StateStore</code></td>
+      <td><code>@json-render/core</code></td>
+    </tr>
+  </tbody>
+</table>

apps/web/app/(main)/docs/api/xstate/page.mdx

@@ -0,0 +1,77 @@
+import { pageMetadata } from "@/lib/page-metadata"
+export const metadata = pageMetadata("docs/api/xstate")
+
+# @json-render/xstate
+
+[XState Store](https://stately.ai/docs/xstate-store) adapter for json-render's `StateStore` interface.
+
+Requires `@xstate/store` v3+.
+
+## Installation
+
+```bash
+npm install @json-render/xstate @json-render/core @json-render/react @xstate/store
+```
+
+## xstateStoreStateStore
+
+Create a `StateStore` backed by an `@xstate/store` atom.
+
+```typescript
+import { xstateStoreStateStore } from "@json-render/xstate";
+```
+
+### Options
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Required</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>atom</code></td>
+      <td><code>{'Atom<StateModel>'}</code></td>
+      <td>Yes</td>
+      <td>An <code>@xstate/store</code> atom (from <code>createAtom</code>) holding the json-render state model.</td>
+    </tr>
+  </tbody>
+</table>
+
+### Example
+
+```typescript
+import { createAtom } from "@xstate/store";
+import { xstateStoreStateStore } from "@json-render/xstate";
+import { StateProvider } from "@json-render/react";
+
+const uiAtom = createAtom({ count: 0 });
+const store = xstateStoreStateStore({ atom: uiAtom });
+```
+
+```tsx
+<StateProvider store={store}>
+  {/* json-render reads/writes go through @xstate/store */}
+</StateProvider>
+```
+
+## Re-exports
+
+<table>
+  <thead>
+    <tr>
+      <th>Export</th>
+      <th>Source</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>StateStore</code></td>
+      <td><code>@json-render/core</code></td>
+    </tr>
+  </tbody>
+</table>

apps/web/app/(main)/docs/api/zustand/page.mdx

@@ -0,0 +1,108 @@
+import { pageMetadata } from "@/lib/page-metadata"
+export const metadata = pageMetadata("docs/api/zustand")
+
+# @json-render/zustand
+
+Zustand adapter for json-render's `StateStore` interface.
+
+Requires Zustand v5+. Zustand v4 is not supported due to breaking API changes in the vanilla store interface.
+
+## Installation
+
+```bash
+npm install @json-render/zustand @json-render/core @json-render/react zustand
+```
+
+## zustandStateStore
+
+Create a `StateStore` backed by a Zustand vanilla store.
+
+```typescript
+import { zustandStateStore } from "@json-render/zustand";
+```
+
+### Options
+
+<table>
+  <thead>
+    <tr>
+      <th>Option</th>
+      <th>Type</th>
+      <th>Required</th>
+      <th>Description</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>store</code></td>
+      <td><code>{'StoreApi<S>'}</code></td>
+      <td>Yes</td>
+      <td>A Zustand vanilla store (from <code>createStore</code> in <code>zustand/vanilla</code>).</td>
+    </tr>
+    <tr>
+      <td><code>selector</code></td>
+      <td><code>{'(state: S) => StateModel'}</code></td>
+      <td>No</td>
+      <td>Select the json-render slice from the store state. Defaults to the entire state.</td>
+    </tr>
+    <tr>
+      <td><code>updater</code></td>
+      <td><code>{'(nextState: StateModel, store: StoreApi<S>) => void'}</code></td>
+      <td>No</td>
+      <td>Apply a state change back to the store. Defaults to a shallow merge.</td>
+    </tr>
+  </tbody>
+</table>
+
+### Example
+
+```typescript
+import { createStore } from "zustand/vanilla";
+import { zustandStateStore } from "@json-render/zustand";
+import { StateProvider } from "@json-render/react";
+
+const bearStore = createStore(() => ({
+  count: 0,
+  name: "Bear",
+}));
+
+const store = zustandStateStore({ store: bearStore });
+```
+
+```tsx
+<StateProvider store={store}>
+  {/* json-render reads/writes go through Zustand */}
+</StateProvider>
+```
+
+### Nested Slice
+
+```typescript
+const appStore = createStore(() => ({
+  ui: { count: 0 },
+  auth: { token: null },
+}));
+
+const store = zustandStateStore({
+  store: appStore,
+  selector: (s) => s.ui,
+  updater: (next, s) => s.setState({ ui: next }),
+});
+```
+
+## Re-exports
+
+<table>
+  <thead>
+    <tr>
+      <th>Export</th>
+      <th>Source</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>StateStore</code></td>
+      <td><code>@json-render/core</code></td>
+    </tr>
+  </tbody>
+</table>

apps/web/app/api/docs-chat/route.ts

@@ -16,7 +16,7 @@ const SYSTEM_PROMPT = `You are a helpful documentation assistant for json-render
 
 GitHub repository: https://github.com/vercel-labs/json-render
 Documentation: https://json-render.dev/docs
-npm packages: @json-render/core, @json-render/react, @json-render/react-email, @json-render/react-pdf, @json-render/image, @json-render/remotion, @json-render/codegen
+npm packages: @json-render/core, @json-render/react, @json-render/vue, @json-render/svelte, @json-render/shadcn, @json-render/react-native, @json-render/react-email, @json-render/react-pdf, @json-render/image, @json-render/remotion, @json-render/codegen, @json-render/mcp, @json-render/redux, @json-render/zustand, @json-render/jotai, @json-render/xstate
 
 You have access to the full json-render documentation via the bash and readFile tools. The docs are available as markdown files in the /workspace/docs/ directory.
 

apps/web/lib/docs-navigation.ts

@@ -95,6 +95,11 @@ export const docsNavigation: NavSection[] = [
         href: "https://github.com/vercel-labs/json-render/tree/main/examples/vite-renderers",
         external: true,
       },
+      {
+        title: "MCP App",
+        href: "https://github.com/vercel-labs/json-render/tree/main/examples/mcp",
+        external: true,
+      },
     ],
   },
   {
@@ -128,6 +133,11 @@ export const docsNavigation: NavSection[] = [
       { title: "@json-render/vue", href: "/docs/api/vue" },
       { title: "@json-render/svelte", href: "/docs/api/svelte" },
       { title: "@json-render/codegen", href: "/docs/api/codegen" },
+      { title: "@json-render/mcp", href: "/docs/api/mcp" },
+      { title: "@json-render/redux", href: "/docs/api/redux" },
+      { title: "@json-render/zustand", href: "/docs/api/zustand" },
+      { title: "@json-render/jotai", href: "/docs/api/jotai" },
+      { title: "@json-render/xstate", href: "/docs/api/xstate" },
     ],
   },
 ];

apps/web/lib/page-titles.ts

@@ -50,6 +50,11 @@ export const PAGE_TITLES: Record<string, string> = {
   "docs/api/image": "@json-render/image API",
   "docs/api/remotion": "@json-render/remotion API",
   "docs/api/shadcn": "@json-render/shadcn API",
+  "docs/api/mcp": "@json-render/mcp API",
+  "docs/api/redux": "@json-render/redux API",
+  "docs/api/zustand": "@json-render/zustand API",
+  "docs/api/jotai": "@json-render/jotai API",
+  "docs/api/xstate": "@json-render/xstate API",
 };
 
 /**

apps/web/package.json

@@ -1,6 +1,6 @@
 {
   "name": "web",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "private": true,
   "license": "Apache-2.0",

examples/chat/CHANGELOG.md

@@ -1,5 +1,14 @@
 # example-chat
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react@0.12.0
+  - @json-render/shadcn@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

examples/chat/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-chat",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "private": true,
   "scripts": {

examples/dashboard/CHANGELOG.md

@@ -1,5 +1,14 @@
 # example-dashboard
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/codegen@0.12.0
+  - @json-render/react@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

examples/dashboard/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-dashboard",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "private": true,
   "scripts": {

examples/image/CHANGELOG.md

@@ -1,5 +1,13 @@
 # example-image
 
+## 0.1.2
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/image@0.12.0
+
 ## 0.1.1
 
 ### Patch Changes

examples/image/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-image",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "type": "module",
   "private": true,
   "scripts": {

examples/mcp/CHANGELOG.md

@@ -0,0 +1,11 @@
+# example-mcp
+
+## 0.1.1
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/mcp@0.12.0
+  - @json-render/react@0.12.0
+  - @json-render/shadcn@0.12.0

examples/mcp/README.md

@@ -0,0 +1,63 @@
+# MCP App Example
+
+A json-render MCP App that serves interactive shadcn/ui-based UIs directly inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients.
+
+## Setup
+
+```bash
+pnpm install
+pnpm build
+```
+
+## Usage
+
+### With Cursor
+
+Add to `.cursor/mcp.json`:
+
+```json
+{
+  "mcpServers": {
+    "json-render": {
+      "command": "npx",
+      "args": ["tsx", "examples/mcp/server.ts", "--stdio"]
+    }
+  }
+}
+```
+
+### With Claude Desktop
+
+Add to `~/Library/Application Support/Claude/claude_desktop_config.json`:
+
+```json
+{
+  "mcpServers": {
+    "json-render": {
+      "command": "npx",
+      "args": ["tsx", "/absolute/path/to/examples/mcp/server.ts", "--stdio"]
+    }
+  }
+}
+```
+
+### HTTP Transport
+
+```bash
+pnpm start
+# Server listens on http://localhost:3001/mcp
+```
+
+### Stdio Transport
+
+```bash
+pnpm start:stdio
+```
+
+## How It Works
+
+1. The Vite build bundles the React app (with shadcn components and `useJsonRenderApp` hook) into a single self-contained HTML file
+2. The MCP server registers a `render-ui` tool with the catalog prompt as its description
+3. When the LLM calls the tool, it generates a json-render spec constrained to the catalog
+4. The host renders the bundled HTML in a sandboxed iframe
+5. The iframe receives the spec via the MCP Apps protocol and renders it with json-render

examples/mcp/index.html

@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <meta http-equiv="Content-Security-Policy" content="default-src 'self' 'unsafe-inline' 'unsafe-eval' data: blob:; img-src * data: blob:; font-src * data:; connect-src *; media-src *;" />
+  <title>json-render MCP App</title>
+</head>
+<body>
+  <div id="root"></div>
+  <script type="module" src="/src/main.tsx"></script>
+</body>
+</html>

examples/mcp/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "example-mcp",
+  "version": "0.1.1",
+  "type": "module",
+  "private": true,
+  "scripts": {
+    "build": "vite build",
+    "start": "tsx server.ts",
+    "start:stdio": "tsx server.ts --stdio",
+    "dev": "tsx watch server.ts"
+  },
+  "dependencies": {
+    "@json-render/core": "workspace:*",
+    "@json-render/mcp": "workspace:*",
+    "@json-render/react": "workspace:*",
+    "@json-render/shadcn": "workspace:*",
+    "@modelcontextprotocol/ext-apps": "^1.2.0",
+    "@modelcontextprotocol/sdk": "^1.27.1",
+    "react": "19.2.3",
+    "react-dom": "19.2.3",
+    "zod": "^4.3.6"
+  },
+  "devDependencies": {
+    "@types/react": "19.2.3",
+    "@types/react-dom": "19.2.3",
+    "@tailwindcss/vite": "^4.2.1",
+    "@vitejs/plugin-react": "^5.1.4",
+    "tailwindcss": "^4.2.1",
+    "tsx": "^4.21.0",
+    "typescript": "^5.7.2",
+    "vite": "^6.3.5",
+    "vite-plugin-singlefile": "^2.3.0"
+  }
+}

examples/mcp/server.ts

@@ -0,0 +1,86 @@
+import { createMcpApp } from "@json-render/mcp";
+import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
+import { createMcpExpressApp } from "@modelcontextprotocol/sdk/server/express.js";
+import fs from "node:fs";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import { catalog } from "./src/catalog.js";
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+function loadHtml(): string {
+  const htmlPath = path.join(__dirname, "dist", "index.html");
+  if (!fs.existsSync(htmlPath)) {
+    throw new Error(
+      `Built HTML not found at ${htmlPath}. Run 'pnpm build' first.`,
+    );
+  }
+  return fs.readFileSync(htmlPath, "utf-8");
+}
+
+async function startStdio() {
+  const html = loadHtml();
+  const server = await createMcpApp({
+    name: "json-render Example",
+    version: "1.0.0",
+    catalog,
+    html,
+  });
+  await server.connect(new StdioServerTransport());
+}
+
+async function startHttp() {
+  const html = loadHtml();
+  const port = parseInt(process.env.PORT ?? "3001", 10);
+
+  const expressApp = createMcpExpressApp({ host: "0.0.0.0" });
+
+  expressApp.all("/mcp", async (req, res) => {
+    const server = await createMcpApp({
+      name: "json-render Example",
+      version: "1.0.0",
+      catalog,
+      html,
+    });
+
+    const transport = new StreamableHTTPServerTransport({
+      sessionIdGenerator: undefined,
+    });
+
+    res.on("close", () => {
+      transport.close().catch(() => {});
+      server.close().catch(() => {});
+    });
+
+    try {
+      await server.connect(transport);
+      await transport.handleRequest(req, res, req.body);
+    } catch (error) {
+      console.error("MCP error:", error);
+      if (!res.headersSent) {
+        res.status(500).json({
+          jsonrpc: "2.0",
+          error: { code: -32603, message: "Internal server error" },
+          id: null,
+        });
+      }
+    }
+  });
+
+  expressApp.listen(port, () => {
+    console.log(`MCP server listening on http://localhost:${port}/mcp`);
+  });
+}
+
+if (process.argv.includes("--stdio")) {
+  startStdio().catch((e) => {
+    console.error(e);
+    process.exit(1);
+  });
+} else {
+  startHttp().catch((e) => {
+    console.error(e);
+    process.exit(1);
+  });
+}

examples/mcp/src/catalog.ts

@@ -0,0 +1,10 @@
+import { defineCatalog } from "@json-render/core";
+import { schema } from "@json-render/react/schema";
+import { shadcnComponentDefinitions } from "@json-render/shadcn/catalog";
+
+export const catalog = defineCatalog(schema, {
+  components: {
+    ...shadcnComponentDefinitions,
+  },
+  actions: {},
+});

examples/mcp/src/globals.css

@@ -0,0 +1,106 @@
+@import "tailwindcss";
+@source "../../../packages/shadcn/src";
+@source "../../../packages/react/src";
+
+@custom-variant dark (&:is([data-theme="dark"] *));
+
+@theme inline {
+  --radius-sm: calc(var(--radius) - 4px);
+  --radius-md: calc(var(--radius) - 2px);
+  --radius-lg: var(--radius);
+  --radius-xl: calc(var(--radius) + 4px);
+  --radius-2xl: calc(var(--radius) + 8px);
+  --color-background: var(--background);
+  --color-foreground: var(--foreground);
+  --color-card: var(--card);
+  --color-card-foreground: var(--card-foreground);
+  --color-popover: var(--popover);
+  --color-popover-foreground: var(--popover-foreground);
+  --color-primary: var(--primary);
+  --color-primary-foreground: var(--primary-foreground);
+  --color-secondary: var(--secondary);
+  --color-secondary-foreground: var(--secondary-foreground);
+  --color-muted: var(--muted);
+  --color-muted-foreground: var(--muted-foreground);
+  --color-accent: var(--accent);
+  --color-accent-foreground: var(--accent-foreground);
+  --color-destructive: var(--destructive);
+  --color-border: var(--border);
+  --color-input: var(--input);
+  --color-ring: var(--ring);
+}
+
+:root {
+  --radius: 0.625rem;
+  --background: oklch(1 0 0);
+  --foreground: oklch(0.145 0 0);
+  --card: oklch(1 0 0);
+  --card-foreground: oklch(0.145 0 0);
+  --popover: oklch(1 0 0);
+  --popover-foreground: oklch(0.145 0 0);
+  --primary: oklch(0.205 0 0);
+  --primary-foreground: oklch(0.985 0 0);
+  --secondary: oklch(0.97 0 0);
+  --secondary-foreground: oklch(0.205 0 0);
+  --muted: oklch(0.97 0 0);
+  --muted-foreground: oklch(0.556 0 0);
+  --accent: oklch(0.97 0 0);
+  --accent-foreground: oklch(0.205 0 0);
+  --destructive: oklch(0.577 0.245 27.325);
+  --border: oklch(0.922 0 0);
+  --input: oklch(0.922 0 0);
+  --ring: oklch(0.708 0 0);
+}
+
+[data-theme="dark"] {
+  --background: var(--color-background-secondary, var(--vscode-editor-background, oklch(0.145 0 0)));
+  --foreground: var(--color-text-primary, var(--vscode-foreground, oklch(0.985 0 0)));
+  --card: var(--color-background-primary, var(--vscode-sideBar-background, oklch(0.205 0 0)));
+  --card-foreground: var(--color-text-primary, var(--vscode-foreground, oklch(0.985 0 0)));
+  --popover: var(--color-background-primary, var(--vscode-sideBar-background, oklch(0.205 0 0)));
+  --popover-foreground: var(--color-text-primary, var(--vscode-foreground, oklch(0.985 0 0)));
+  --primary: var(--color-text-primary, var(--vscode-foreground, oklch(0.922 0 0)));
+  --primary-foreground: var(--color-background-primary, var(--vscode-sideBar-background, oklch(0.205 0 0)));
+  --secondary: var(--color-background-tertiary, var(--vscode-activityBar-background, oklch(0.269 0 0)));
+  --secondary-foreground: var(--color-text-primary, var(--vscode-foreground, oklch(0.985 0 0)));
+  --muted: var(--color-background-tertiary, var(--vscode-activityBar-background, oklch(0.269 0 0)));
+  --muted-foreground: var(--color-text-secondary, var(--vscode-descriptionForeground, oklch(0.708 0 0)));
+  --accent: var(--color-background-tertiary, var(--vscode-activityBar-background, oklch(0.269 0 0)));
+  --accent-foreground: var(--color-text-primary, var(--vscode-foreground, oklch(0.985 0 0)));
+  --destructive: var(--color-text-danger, var(--vscode-errorForeground, oklch(0.704 0.191 22.216)));
+  --border: var(--color-border-primary, var(--vscode-widget-border, oklch(1 0 0 / 10%)));
+  --input: var(--color-border-secondary, var(--vscode-editorWidget-border, oklch(1 0 0 / 15%)));
+  --ring: var(--color-ring-primary, var(--vscode-focusBorder, oklch(0.556 0 0)));
+}
+
+* {
+  box-sizing: border-box;
+  border-color: var(--color-border);
+}
+
+html, body, #root {
+  width: 100%;
+  height: 100%;
+  margin: 0;
+  padding: 0;
+}
+
+body {
+  background-color: var(--color-background);
+  color: var(--color-foreground);
+  font-family: var(--vscode-font-family, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif);
+}
+
+@layer base {
+  * {
+    @apply border-border outline-ring/50;
+  }
+  body {
+    @apply text-foreground;
+    background-color: var(--color-background) !important;
+  }
+}
+
+button {
+  cursor: pointer;
+}

examples/mcp/src/main.tsx

@@ -0,0 +1,269 @@
+import "./globals.css";
+import {
+  Component,
+  useState,
+  useEffect,
+  useCallback,
+  type ReactNode,
+} from "react";
+import { createRoot } from "react-dom/client";
+import { App as McpApp } from "@modelcontextprotocol/ext-apps";
+import { JSONUIProvider, Renderer, defineRegistry } from "@json-render/react";
+import { shadcnComponents } from "@json-render/shadcn";
+import type { Spec } from "@json-render/core";
+import { catalog } from "./catalog";
+
+const { registry } = defineRegistry(catalog, {
+  components: {
+    ...shadcnComponents,
+    Avatar: ({ props }: { props: Record<string, unknown> }) => {
+      const name = (props.name as string) || (props.alt as string) || "?";
+      const src = props.src as string | undefined;
+      const initials = name
+        .split(" ")
+        .map((n) => n[0])
+        .join("")
+        .slice(0, 2)
+        .toUpperCase();
+      const size = props.size === "lg" ? 48 : props.size === "sm" ? 32 : 40;
+      const [imgFailed, setImgFailed] = useState(false);
+      const onError = useCallback(() => setImgFailed(true), []);
+      const showImg = src && !imgFailed;
+
+      return (
+        <div
+          style={{
+            width: size,
+            height: size,
+            borderRadius: "50%",
+            overflow: "hidden",
+            backgroundColor: "var(--color-background-tertiary, #27272a)",
+            display: "flex",
+            alignItems: "center",
+            justifyContent: "center",
+            flexShrink: 0,
+          }}
+        >
+          {showImg ? (
+            <img
+              src={src}
+              alt={name}
+              referrerPolicy="no-referrer"
+              crossOrigin="anonymous"
+              width={size}
+              height={size}
+              onError={onError}
+              style={{ objectFit: "cover", width: size, height: size }}
+            />
+          ) : (
+            <span
+              style={{
+                fontSize: size * 0.4,
+                color: "var(--color-text-secondary, #a1a1aa)",
+              }}
+            >
+              {initials}
+            </span>
+          )}
+        </div>
+      );
+    },
+  },
+});
+
+class ErrorBoundary extends Component<
+  { children: ReactNode },
+  { error: Error | null }
+> {
+  state = { error: null as Error | null };
+  static getDerivedStateFromError(error: Error) {
+    return { error };
+  }
+  render() {
+    if (this.state.error) {
+      return (
+        <div
+          style={{
+            padding: 16,
+            color: "#dc2626",
+            fontFamily: "monospace",
+            fontSize: 13,
+          }}
+        >
+          Error: {this.state.error.message}
+        </div>
+      );
+    }
+    return this.props.children;
+  }
+}
+
+function forceFullWidth(spec: Spec): Spec {
+  if (!spec.elements) return spec;
+  const elements = { ...spec.elements };
+  for (const [key, el] of Object.entries(elements)) {
+    if (el.type === "Card" && el.props) {
+      elements[key] = {
+        ...el,
+        props: { ...el.props, maxWidth: "full", centered: false },
+      };
+    }
+  }
+  return { ...spec, elements };
+}
+
+function parseSpec(
+  result: { content?: Array<{ type: string; text?: string }> } | undefined,
+): Spec | null {
+  const text = result?.content?.find((c) => c.type === "text")?.text;
+  if (!text) return null;
+  try {
+    return forceFullWidth(JSON.parse(text) as Spec);
+  } catch {
+    return null;
+  }
+}
+
+function applyHostContext(ctx: {
+  theme?: string;
+  styles?: { variables?: Record<string, string> };
+}) {
+  if (ctx.theme) {
+    document.documentElement.setAttribute("data-theme", ctx.theme);
+    document.documentElement.style.colorScheme = ctx.theme;
+  }
+  if (ctx.styles?.variables) {
+    const root = document.documentElement;
+    for (const [key, value] of Object.entries(ctx.styles.variables)) {
+      root.style.setProperty(key, value);
+    }
+  }
+}
+
+function McpAppView() {
+  const [spec, setSpec] = useState<Spec | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    let specReceived = false;
+
+    function handleSpec(s: Spec) {
+      if (specReceived) return;
+      specReceived = true;
+      setSpec(s);
+    }
+
+    function onMessage(event: MessageEvent) {
+      if (specReceived) return;
+      const data = event.data as Record<string, unknown> | undefined;
+      if (!data || typeof data !== "object") return;
+      const method = data.method as string | undefined;
+      const params = data.params as Record<string, unknown> | undefined;
+
+      // Cursor sends the spec via tool-input
+      if (method === "ui/notifications/tool-input" && params?.arguments) {
+        const args = params.arguments as Record<string, unknown>;
+        const rawSpec = args.spec;
+        if (
+          rawSpec &&
+          typeof rawSpec === "object" &&
+          "root" in rawSpec &&
+          "elements" in rawSpec
+        ) {
+          handleSpec(forceFullWidth(rawSpec as Spec));
+        }
+      }
+    }
+    window.addEventListener("message", onMessage);
+
+    const app = new McpApp({ name: "json-render", version: "1.0.0" });
+
+    app.ontoolresult = (result) => {
+      const parsed = parseSpec(
+        result as { content?: Array<{ type: string; text?: string }> },
+      );
+      if (parsed) handleSpec(parsed);
+    };
+
+    app.onhostcontextchanged = (ctx) =>
+      applyHostContext(ctx as Parameters<typeof applyHostContext>[0]);
+
+    app.onerror = (err: unknown) => {
+      setError(err instanceof Error ? err.message : String(err));
+    };
+
+    app
+      .connect()
+      .then(() => {
+        const ctx = app.getHostContext?.();
+        if (ctx)
+          applyHostContext(ctx as Parameters<typeof applyHostContext>[0]);
+
+        // Fallback: if host didn't provide theme, detect via media query
+        if (!ctx || !(ctx as Record<string, unknown>).theme) {
+          const prefersDark = window.matchMedia(
+            "(prefers-color-scheme: dark)",
+          ).matches;
+          document.documentElement.setAttribute(
+            "data-theme",
+            prefersDark ? "dark" : "light",
+          );
+          document.documentElement.style.colorScheme = prefersDark
+            ? "dark"
+            : "light";
+        }
+      })
+      .catch((err: unknown) =>
+        setError(err instanceof Error ? err.message : String(err)),
+      );
+
+    return () => {
+      window.removeEventListener("message", onMessage);
+      app.close().catch(() => {});
+    };
+  }, []);
+
+  if (error) {
+    return (
+      <div
+        style={{
+          padding: 16,
+          color: "#dc2626",
+          fontFamily: "monospace",
+          fontSize: 13,
+        }}
+      >
+        {error}
+      </div>
+    );
+  }
+
+  if (!spec) {
+    return (
+      <div
+        style={{
+          padding: 16,
+          color: "#6b7280",
+          fontFamily: "sans-serif",
+          fontSize: 14,
+        }}
+      >
+        Loading...
+      </div>
+    );
+  }
+
+  return (
+    <JSONUIProvider registry={registry} initialState={spec.state ?? {}}>
+      <div className="w-full">
+        <Renderer spec={spec} registry={registry} />
+      </div>
+    </JSONUIProvider>
+  );
+}
+
+createRoot(document.getElementById("root")!).render(
+  <ErrorBoundary>
+    <McpAppView />
+  </ErrorBoundary>,
+);

examples/mcp/src/mcp-app-view.tsx

@@ -0,0 +1,89 @@
+import { JSONUIProvider, Renderer } from "@json-render/react";
+import { shadcnComponents } from "@json-render/shadcn";
+import { defineRegistry } from "@json-render/react";
+import { useJsonRenderApp } from "@json-render/mcp/app";
+import { catalog } from "./catalog";
+import { useState, useEffect } from "react";
+
+const { registry } = defineRegistry(catalog, {
+  components: {
+    ...shadcnComponents,
+  },
+});
+
+const debugStyle = {
+  padding: 12,
+  fontFamily: "monospace",
+  fontSize: 12,
+  color: "#000",
+  background: "#fffbe6",
+  border: "1px solid #faad14",
+  borderRadius: 4,
+  margin: 8,
+  whiteSpace: "pre-wrap" as const,
+  wordBreak: "break-all" as const,
+};
+
+export function McpAppView() {
+  const [logs, setLogs] = useState<string[]>(["App mounted"]);
+
+  const addLog = (msg: string) => {
+    setLogs((prev) => [
+      ...prev,
+      `${new Date().toISOString().slice(11, 23)} ${msg}`,
+    ]);
+  };
+
+  const { spec, loading, connected, connecting, error } = useJsonRenderApp({
+    name: "json-render-mcp-example",
+    version: "1.0.0",
+  });
+
+  useEffect(() => {
+    addLog(
+      `State: connecting=${connecting} connected=${connected} error=${error?.message ?? "none"} loading=${loading} spec=${spec ? "yes" : "null"}`,
+    );
+  }, [connecting, connected, error, loading, spec]);
+
+  useEffect(() => {
+    if (spec) {
+      addLog(
+        `Spec received: root=${spec.root}, elements=${Object.keys(spec.elements ?? {}).join(",")}`,
+      );
+    }
+  }, [spec]);
+
+  if (error) {
+    return (
+      <div style={debugStyle}>
+        <div style={{ color: "#ef4444", fontWeight: "bold" }}>
+          Connection error: {error.message}
+        </div>
+        <div style={{ marginTop: 8 }}>{logs.join("\n")}</div>
+      </div>
+    );
+  }
+
+  if (!spec) {
+    return (
+      <div style={debugStyle}>
+        <div>
+          {connecting
+            ? "Connecting to host..."
+            : loading
+              ? "Waiting for UI spec..."
+              : "No spec received."}
+        </div>
+        <div style={{ marginTop: 8 }}>{logs.join("\n")}</div>
+      </div>
+    );
+  }
+
+  return (
+    <div>
+      <JSONUIProvider registry={registry} initialState={spec.state ?? {}}>
+        <Renderer spec={spec} registry={registry} loading={loading} />
+      </JSONUIProvider>
+    </div>
+  );
+}

examples/mcp/tsconfig.json

@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true,
+    "noEmit": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "jsx": "react-jsx"
+  },
+  "include": ["src", "server.ts"]
+}

examples/mcp/vite.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from "vite";
+import react from "@vitejs/plugin-react";
+import { viteSingleFile } from "vite-plugin-singlefile";
+import tailwindcss from "@tailwindcss/vite";
+
+export default defineConfig({
+  plugins: [react(), tailwindcss(), viteSingleFile()],
+  build: {
+    outDir: "dist",
+    emptyOutDir: false,
+    rollupOptions: {
+      input: "index.html",
+    },
+  },
+});

examples/no-ai/CHANGELOG.md

@@ -1,5 +1,14 @@
 # example-no-ai
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react@0.12.0
+  - @json-render/shadcn@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

examples/no-ai/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-no-ai",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "private": true,
   "scripts": {

examples/react-email/CHANGELOG.md

@@ -0,0 +1,9 @@
+# example-react-email
+
+## 0.1.1
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react-email@0.12.0

examples/react-email/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-react-email",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "type": "module",
   "private": true,
   "scripts": {

examples/react-native/CHANGELOG.md

@@ -1,5 +1,13 @@
 # example-react-native
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react-native@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

examples/react-native/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-react-native",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "private": true,
   "main": "expo-router/entry",
   "scripts": {

examples/react-pdf/CHANGELOG.md

@@ -1,5 +1,13 @@
 # example-react-pdf
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react-pdf@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

examples/react-pdf/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-react-pdf",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "private": true,
   "scripts": {

examples/remotion/CHANGELOG.md

@@ -1,5 +1,13 @@
 # example-remotion
 
+## 0.1.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/remotion@0.12.0
+
 ## 0.1.4
 
 ### Patch Changes

examples/remotion/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-remotion",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "private": true,
   "scripts": {

examples/stripe-app/drawer-app/CHANGELOG.md

@@ -1,5 +1,13 @@
 # com.example.json-render-demo
 
+## 0.0.6
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react@0.12.0
+
 ## 0.0.5
 
 ### Patch Changes

examples/stripe-app/drawer-app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "com.example.json-render-demo",
-  "version": "0.0.5",
+  "version": "0.0.6",
   "description": "Test",
   "private": true,
   "license": "~~proprietary~~",

examples/stripe-app/fullpage-app/CHANGELOG.md

@@ -1,5 +1,13 @@
 # com.example.json-render-fullpage-demo
 
+## 0.0.6
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react@0.12.0
+
 ## 0.0.5
 
 ### Patch Changes

examples/stripe-app/fullpage-app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "com.example.json-render-fullpage-demo",
-  "version": "0.0.5",
+  "version": "0.0.6",
   "description": "Full-page Stripe App example (alpha)",
   "private": true,
   "license": "~~proprietary~~",

examples/svelte-chat/CHANGELOG.md

@@ -0,0 +1,9 @@
+# svelte-chat
+
+## 0.0.2
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/svelte@0.12.0

examples/svelte-chat/package.json

@@ -1,7 +1,7 @@
 {
   "name": "svelte-chat",
   "private": true,
-  "version": "0.0.1",
+  "version": "0.0.2",
   "type": "module",
   "scripts": {
     "dev": "vite dev",

examples/svelte-chat/src/lib/render/registry.ts

@@ -1,7 +1,6 @@
-import { defineRegistry, type ComponentRegistry } from "@json-render/svelte";
+import { defineRegistry } from "@json-render/svelte";
 import { explorerCatalog } from "./catalog";
 
-// Import render components
 import StackComponent from "./components/Stack.svelte";
 import CardComponent from "./components/Card.svelte";
 import GridComponent from "./components/Grid.svelte";
@@ -28,7 +27,7 @@ import SelectInputComponent from "./components/SelectInput.svelte";
 import TextInputComponent from "./components/TextInput.svelte";
 import ButtonComponent from "./components/Button.svelte";
 
-const components: ComponentRegistry = {
+const components = {
   Stack: StackComponent,
   Card: CardComponent,
   Grid: GridComponent,

examples/svelte/CHANGELOG.md

@@ -0,0 +1,9 @@
+# example-svelte
+
+## 0.1.2
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/svelte@0.12.0

examples/svelte/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-svelte",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "private": true,
   "type": "module",
   "scripts": {

examples/vite-renderers/CHANGELOG.md

@@ -1,5 +1,15 @@
 # vite-renderers
 
+## 0.1.3
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/svelte@0.12.0
+  - @json-render/react@0.12.0
+  - @json-render/vue@0.12.0
+
 ## 0.1.2
 
 ### Patch Changes

examples/vite-renderers/package.json

@@ -1,6 +1,6 @@
 {
   "name": "vite-renderers",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "private": true,
   "type": "module",
   "scripts": {

examples/vue/CHANGELOG.md

@@ -1,5 +1,13 @@
 # example-vue
 
+## 0.1.3
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/vue@0.12.0
+
 ## 0.1.2
 
 ### Patch Changes

examples/vue/package.json

@@ -1,6 +1,6 @@
 {
   "name": "example-vue",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "private": true,
   "scripts": {
     "predev": "command -v portless >/dev/null 2>&1 || (echo '\\nportless is required but not installed. Run: npm i -g portless\\nSee: https://github.com/vercel-labs/portless\\n' && exit 1)",

packages/codegen/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/codegen
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/codegen/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/codegen",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Utilities for generating code from json-render UI trees",
   "keywords": [

packages/core/CHANGELOG.md

@@ -1,5 +1,19 @@
 # @json-render/core
 
+## 0.12.0
+
+### Minor Changes
+
+- 63c339b: Add Svelte renderer, React Email renderer, and MCP Apps integration.
+
+  ### New:
+  - **`@json-render/svelte`** — Svelte 5 renderer with runes-based reactivity. Full support for data binding, visibility, actions, validation, watchers, streaming, and repeat scopes. Includes `defineRegistry`, `Renderer`, `schema`, composables, and context providers.
+  - **`@json-render/react-email`** — React Email renderer for generating HTML and plain-text emails from JSON specs. 17 standard components (Html, Head, Body, Container, Section, Row, Column, Heading, Text, Link, Button, Image, Hr, Preview, Markdown). Server-side `renderToHtml` / `renderToPlainText` APIs. Custom catalog and registry support.
+  - **`@json-render/mcp`** — MCP Apps integration that serves json-render UIs as interactive apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients. `createMcpApp` server factory, `useJsonRenderApp` React hook for iframes, and `buildAppHtml` utility.
+
+  ### Fixed:
+  - **`@json-render/svelte`** — Corrected JSDoc comment and added missing `zod` peer dependency.
+
 ## 0.11.0
 
 ### Minor Changes

packages/core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/core",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "JSON becomes real things. Define your catalog, register your components, let AI generate.",
   "keywords": [

packages/image/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/image
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Minor Changes

packages/image/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/image",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Image renderer for @json-render/core. JSON becomes SVG and PNG images via Satori.",
   "keywords": [

packages/jotai/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/jotai
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/jotai/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/jotai",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Jotai adapter for json-render StateStore",
   "keywords": [

packages/mcp/CHANGELOG.md

@@ -0,0 +1,20 @@
+# @json-render/mcp
+
+## 0.12.0
+
+### Minor Changes
+
+- 63c339b: Add Svelte renderer, React Email renderer, and MCP Apps integration.
+
+  ### New:
+  - **`@json-render/svelte`** — Svelte 5 renderer with runes-based reactivity. Full support for data binding, visibility, actions, validation, watchers, streaming, and repeat scopes. Includes `defineRegistry`, `Renderer`, `schema`, composables, and context providers.
+  - **`@json-render/react-email`** — React Email renderer for generating HTML and plain-text emails from JSON specs. 17 standard components (Html, Head, Body, Container, Section, Row, Column, Heading, Text, Link, Button, Image, Hr, Preview, Markdown). Server-side `renderToHtml` / `renderToPlainText` APIs. Custom catalog and registry support.
+  - **`@json-render/mcp`** — MCP Apps integration that serves json-render UIs as interactive apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients. `createMcpApp` server factory, `useJsonRenderApp` React hook for iframes, and `buildAppHtml` utility.
+
+  ### Fixed:
+  - **`@json-render/svelte`** — Corrected JSDoc comment and added missing `zod` peer dependency.
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0

packages/mcp/README.md

@@ -0,0 +1,124 @@
+# @json-render/mcp
+
+MCP Apps integration for [json-render](https://github.com/vercel-labs/json-render). Serve json-render UIs as interactive MCP Apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients.
+
+## What are MCP Apps?
+
+[MCP Apps](https://modelcontextprotocol.io/docs/extensions/apps) is an extension to the Model Context Protocol that lets MCP servers return interactive HTML UIs rendered directly inside chat conversations. Instead of text-only tool responses, users get full interactive interfaces -- dashboards, forms, data visualizations -- embedded inline.
+
+## Installation
+
+```bash
+npm install @json-render/mcp @json-render/core @modelcontextprotocol/sdk
+```
+
+## Quick Start
+
+### 1. Define your catalog
+
+```ts
+import { defineCatalog } from "@json-render/core";
+import { schema } from "@json-render/react/schema";
+import { shadcnComponentDefinitions } from "@json-render/shadcn/catalog";
+
+const catalog = defineCatalog(schema, {
+  components: { ...shadcnComponentDefinitions },
+  actions: {},
+});
+```
+
+### 2. Create the MCP server
+
+```ts
+import { createMcpApp } from "@json-render/mcp";
+import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+import fs from "node:fs";
+
+const server = createMcpApp({
+  name: "My Dashboard",
+  version: "1.0.0",
+  catalog,
+  html: fs.readFileSync("dist/index.html", "utf-8"),
+});
+
+await server.connect(new StdioServerTransport());
+```
+
+### 3. Build the UI (iframe)
+
+Create a React app that uses `useJsonRenderApp` from `@json-render/mcp/app`:
+
+```tsx
+import { useJsonRenderApp } from "@json-render/mcp/app";
+import { JSONUIProvider, Renderer } from "@json-render/react";
+
+function McpAppView({ registry }) {
+  const { spec, loading, connected, error } = useJsonRenderApp();
+
+  if (error) return <div>Error: {error.message}</div>;
+  if (!spec) return <div>Waiting for spec...</div>;
+
+  return (
+    <JSONUIProvider registry={registry} initialState={spec.state ?? {}}>
+      <Renderer spec={spec} registry={registry} loading={loading} />
+    </JSONUIProvider>
+  );
+}
+```
+
+Bundle with Vite + `vite-plugin-singlefile` into a single HTML file, then pass it to `createMcpApp` as the `html` option.
+
+### 4. Connect to a client
+
+Add to `.cursor/mcp.json` or Claude Desktop config:
+
+```json
+{
+  "mcpServers": {
+    "my-app": {
+      "command": "node",
+      "args": ["./server.js", "--stdio"]
+    }
+  }
+}
+```
+
+## API Reference
+
+### Server Side (main export)
+
+#### `createMcpApp(options)`
+
+Creates a fully-configured `McpServer` with a json-render tool and UI resource.
+
+| Option | Type | Description |
+|--------|------|-------------|
+| `name` | `string` | Server name shown in client UIs |
+| `version` | `string` | Server version |
+| `catalog` | `Catalog` | json-render catalog defining available components |
+| `html` | `string` | Bundled HTML for the iframe UI |
+| `tool` | `McpToolOptions` | Optional tool name/title/description overrides |
+
+#### `registerJsonRenderTool(server, options)`
+
+Register a json-render tool on an existing `McpServer`.
+
+#### `registerJsonRenderResource(server, options)`
+
+Register a json-render UI resource on an existing `McpServer`.
+
+### Client Side (`@json-render/mcp/app`)
+
+#### `useJsonRenderApp(options?)`
+
+React hook for the iframe-side app. Connects to the MCP host, receives tool results, and maintains the current json-render spec.
+
+Returns `{ spec, loading, connected, connecting, error, app, callServerTool }`.
+
+#### `buildAppHtml(options)`
+
+Generate a self-contained HTML string from bundled JS/CSS for use as a UI resource.
+
+## Client Support
+
+MCP Apps are supported by Claude, ChatGPT, VS Code (Copilot), Cursor, Goose, and Postman.

packages/mcp/package.json

@@ -0,0 +1,78 @@
+{
+  "name": "@json-render/mcp",
+  "version": "0.12.0",
+  "license": "Apache-2.0",
+  "description": "MCP Apps integration for @json-render/core. Serve json-render UIs as interactive MCP Apps in Claude, ChatGPT, Cursor, and VS Code.",
+  "keywords": [
+    "json",
+    "ui",
+    "mcp",
+    "model-context-protocol",
+    "mcp-apps",
+    "ai",
+    "generative-ui",
+    "llm",
+    "renderer",
+    "claude",
+    "chatgpt",
+    "cursor"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/vercel-labs/json-render.git",
+    "directory": "packages/mcp"
+  },
+  "homepage": "https://github.com/vercel-labs/json-render#readme",
+  "bugs": {
+    "url": "https://github.com/vercel-labs/json-render/issues"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "main": "./dist/index.js",
+  "module": "./dist/index.mjs",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.mjs",
+      "require": "./dist/index.js"
+    },
+    "./app": {
+      "types": "./dist/app.d.ts",
+      "import": "./dist/app.mjs",
+      "require": "./dist/app.js"
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "tsup",
+    "dev": "tsup --watch",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@json-render/core": "workspace:*",
+    "@modelcontextprotocol/ext-apps": "^1.2.0",
+    "@modelcontextprotocol/sdk": "^1.27.1"
+  },
+  "devDependencies": {
+    "@internal/typescript-config": "workspace:*",
+    "@types/react": "19.2.3",
+    "tsup": "^8.0.2",
+    "typescript": "^5.4.5"
+  },
+  "peerDependencies": {
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0"
+  },
+  "peerDependenciesMeta": {
+    "react": {
+      "optional": true
+    },
+    "react-dom": {
+      "optional": true
+    }
+  }
+}

packages/mcp/src/app.ts

@@ -0,0 +1,30 @@
+/**
+ * Client-side (iframe) utilities for rendering json-render specs
+ * inside an MCP App view.
+ *
+ * This module is intended to run **inside the sandboxed iframe** that
+ * MCP hosts render. It connects to the host via the MCP Apps protocol,
+ * receives tool results containing json-render specs, and provides
+ * React hooks / helpers to render them.
+ *
+ * @example
+ * ```tsx
+ * import { useJsonRenderApp } from "@json-render/mcp/app";
+ * import { Renderer } from "@json-render/react";
+ *
+ * function McpAppView({ registry }) {
+ *   const { spec, loading } = useJsonRenderApp();
+ *   return <Renderer spec={spec} registry={registry} loading={loading} />;
+ * }
+ * ```
+ *
+ * @packageDocumentation
+ */
+
+export { useJsonRenderApp } from "./use-json-render-app.js";
+export type {
+  UseJsonRenderAppOptions,
+  UseJsonRenderAppReturn,
+} from "./use-json-render-app.js";
+export { buildAppHtml } from "./build-app-html.js";
+export type { BuildAppHtmlOptions } from "./build-app-html.js";

packages/mcp/src/build-app-html.ts

@@ -0,0 +1,71 @@
+/**
+ * Options for `buildAppHtml`.
+ */
+export interface BuildAppHtmlOptions {
+  /** Title for the HTML page. Defaults to `"json-render"`. */
+  title?: string;
+  /**
+   * Inline CSS to inject into the page `<style>` tag.
+   * Use this to include Tailwind output or custom styles.
+   */
+  css?: string;
+  /**
+   * Bundled JavaScript for the app entry point.
+   * This should be the output of a bundler (Vite, esbuild, etc.)
+   * that bundles your React app, registry, and the
+   * `useJsonRenderApp` hook into a single script.
+   */
+  js: string;
+  /**
+   * Additional `<head>` content (meta tags, font links, etc.).
+   */
+  head?: string;
+}
+
+/**
+ * Build a self-contained HTML string for an MCP App UI resource.
+ *
+ * The resulting HTML is designed to be served as a `ui://` resource
+ * via `registerJsonRenderResource` or `createMcpApp`.
+ *
+ * Typically you'd use a bundler (Vite + `vite-plugin-singlefile`, or
+ * esbuild) to produce the `js` and `css` strings, then pass them here.
+ *
+ * @example
+ * ```ts
+ * import { buildAppHtml } from "@json-render/mcp/app";
+ * import { readFileSync } from "node:fs";
+ *
+ * const html = buildAppHtml({
+ *   title: "Dashboard",
+ *   js: readFileSync("dist/app.js", "utf-8"),
+ *   css: readFileSync("dist/app.css", "utf-8"),
+ * });
+ * ```
+ */
+export function buildAppHtml(options: BuildAppHtmlOptions): string {
+  const { title = "json-render", css = "", js, head = "" } = options;
+
+  return `<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>${escapeHtml(title)}</title>
+  ${head}
+  <style>${css}</style>
+</head>
+<body>
+  <div id="root"></div>
+  <script type="module">${js}</script>
+</body>
+</html>`;
+}
+
+function escapeHtml(str: string): string {
+  return str
+    .replace(/&/g, "&amp;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;");
+}

packages/mcp/src/index.ts

@@ -0,0 +1,12 @@
+export type {
+  CreateMcpAppOptions,
+  McpToolOptions,
+  RegisterToolOptions,
+  RegisterResourceOptions,
+} from "./types.js";
+
+export {
+  createMcpApp,
+  registerJsonRenderTool,
+  registerJsonRenderResource,
+} from "./server.js";

packages/mcp/src/server.ts

@@ -0,0 +1,158 @@
+import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import type {
+  CreateMcpAppOptions,
+  RegisterToolOptions,
+  RegisterResourceOptions,
+} from "./types.js";
+
+const RESOURCE_MIME_TYPE = "text/html;profile=mcp-app";
+
+/**
+ * Dynamically import the ext-apps server helpers to avoid CJS/ESM type
+ * mismatches at compile time while still getting the proper runtime
+ * `_meta.ui` normalization that hosts require.
+ */
+async function getExtApps() {
+  const mod = await import("@modelcontextprotocol/ext-apps/server");
+  return mod;
+}
+
+/**
+ * Register a json-render tool on an existing MCP server.
+ *
+ * Uses `registerAppTool` from `@modelcontextprotocol/ext-apps/server`
+ * so that MCP Apps-capable hosts (Claude, VS Code, Cursor, ChatGPT)
+ * see the `_meta.ui.resourceUri` in the tool listing and know to
+ * fetch and render the `ui://` resource as an interactive iframe.
+ *
+ * The tool accepts a json-render spec as input and returns it as text
+ * content, which the iframe receives via `ontoolresult`.
+ */
+export async function registerJsonRenderTool(
+  server: McpServer,
+  options: RegisterToolOptions,
+): Promise<void> {
+  const { catalog, name, title, description, resourceUri } = options;
+  const { registerAppTool } = await getExtApps();
+
+  const specZodSchema = catalog.zodSchema();
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  (registerAppTool as any)(
+    server,
+    name,
+    {
+      title,
+      description,
+      inputSchema: { spec: specZodSchema },
+      _meta: { ui: { resourceUri } },
+    },
+    async (args: { spec?: unknown }) => {
+      const spec = args.spec;
+      const validation = catalog.validate(spec);
+      const validSpec = validation.success ? validation.data : spec;
+
+      return {
+        content: [
+          {
+            type: "text" as const,
+            text: JSON.stringify(validSpec),
+          },
+        ],
+      };
+    },
+  );
+}
+
+/**
+ * Register a json-render UI resource on an existing MCP server.
+ *
+ * The resource serves the self-contained HTML page that renders
+ * json-render specs received from tool results.
+ */
+export async function registerJsonRenderResource(
+  server: McpServer,
+  options: RegisterResourceOptions,
+): Promise<void> {
+  const { resourceUri, html } = options;
+  const { registerAppResource, RESOURCE_MIME_TYPE: mimeType } =
+    await getExtApps();
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  (registerAppResource as any)(
+    server,
+    resourceUri,
+    resourceUri,
+    { mimeType },
+    async () => ({
+      contents: [
+        {
+          uri: resourceUri,
+          mimeType,
+          text: html,
+          _meta: {
+            ui: {
+              csp: {
+                resourceDomains: ["https:"],
+                connectDomains: ["https:"],
+              },
+            },
+          },
+        },
+      ],
+    }),
+  );
+}
+
+/**
+ * Create a fully-configured MCP server that serves a json-render catalog
+ * as an MCP App.
+ *
+ * This is the main entry point for most users. It creates an `McpServer`,
+ * registers the render tool and UI resource, and returns the server
+ * ready for transport connection.
+ *
+ * @example
+ * ```ts
+ * import { createMcpApp } from "@json-render/mcp";
+ *
+ * const server = createMcpApp({
+ *   name: "My Dashboard",
+ *   version: "1.0.0",
+ *   catalog: myCatalog,
+ *   html: myBundledHtml,
+ * });
+ *
+ * // Connect via stdio
+ * import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+ * await server.connect(new StdioServerTransport());
+ * ```
+ */
+export async function createMcpApp(
+  options: CreateMcpAppOptions,
+): Promise<McpServer> {
+  const { name, version, catalog, html, tool } = options;
+
+  const toolName = tool?.name ?? "render-ui";
+  const toolTitle = tool?.title ?? "Render UI";
+  const resourceUri = `ui://${toolName}/view.html`;
+
+  const catalogPrompt = catalog.prompt();
+  const toolDescription =
+    tool?.description ??
+    `Render an interactive UI. The spec argument must be a json-render spec conforming to the catalog.\n\n${catalogPrompt}`;
+
+  const server = new McpServer({ name, version });
+
+  await registerJsonRenderTool(server, {
+    catalog,
+    name: toolName,
+    title: toolTitle,
+    description: toolDescription,
+    resourceUri,
+  });
+
+  await registerJsonRenderResource(server, { resourceUri, html });
+
+  return server;
+}

packages/mcp/src/types.ts

@@ -0,0 +1,62 @@
+import type { Catalog } from "@json-render/core";
+
+/**
+ * Options for creating an MCP App server backed by a json-render catalog.
+ */
+export interface CreateMcpAppOptions {
+  /** Display name for the MCP server shown in client UIs. */
+  name: string;
+  /** Semantic version of the MCP server. */
+  version: string;
+  /** The json-render catalog defining available components and actions. */
+  catalog: Catalog;
+  /**
+   * Pre-built HTML string for the UI resource.
+   * Generate this with `buildAppHtml` from `@json-render/mcp/app` or
+   * provide your own self-contained HTML page.
+   */
+  html: string;
+  /**
+   * Optional tool configuration overrides.
+   */
+  tool?: McpToolOptions;
+}
+
+/**
+ * Options for configuring the MCP tool that renders json-render specs.
+ */
+export interface McpToolOptions {
+  /** Tool name exposed to the LLM. Defaults to `"render-ui"`. */
+  name?: string;
+  /** Human-readable title. Defaults to `"Render UI"`. */
+  title?: string;
+  /** Tool description shown to the LLM. When omitted, a description is
+   *  auto-generated from the catalog prompt. */
+  description?: string;
+}
+
+/**
+ * Options for registering the MCP App tool.
+ */
+export interface RegisterToolOptions {
+  /** The json-render catalog. */
+  catalog: Catalog;
+  /** Tool name. */
+  name: string;
+  /** Tool title. */
+  title: string;
+  /** Tool description. */
+  description: string;
+  /** The `ui://` resource URI this tool's view is served from. */
+  resourceUri: string;
+}
+
+/**
+ * Options for registering the MCP App UI resource.
+ */
+export interface RegisterResourceOptions {
+  /** The `ui://` resource URI. */
+  resourceUri: string;
+  /** Self-contained HTML string for the view. */
+  html: string;
+}

packages/mcp/src/use-json-render-app.ts

@@ -0,0 +1,139 @@
+import { useState, useEffect, useCallback, useRef } from "react";
+import type { Spec } from "@json-render/core";
+import { App } from "@modelcontextprotocol/ext-apps";
+
+/**
+ * Options for the `useJsonRenderApp` hook.
+ */
+export interface UseJsonRenderAppOptions {
+  /** App name shown during initialization. Defaults to `"json-render"`. */
+  name?: string;
+  /** App version. Defaults to `"1.0.0"`. */
+  version?: string;
+}
+
+/**
+ * Return value of `useJsonRenderApp`.
+ */
+export interface UseJsonRenderAppReturn {
+  /** The current json-render spec (null until the first tool result). */
+  spec: Spec | null;
+  /** Whether the app is still connecting to the host. */
+  connecting: boolean;
+  /** Whether the app is connected to the host. */
+  connected: boolean;
+  /** Connection error, if any. */
+  error: Error | null;
+  /** Whether the spec is still being received / parsed. */
+  loading: boolean;
+  /** The underlying MCP App instance. */
+  app: App | null;
+  /**
+   * Call a tool on the MCP server and update the spec from the result.
+   * Useful for refresh / drill-down interactions.
+   */
+  callServerTool: (
+    name: string,
+    args?: Record<string, unknown>,
+  ) => Promise<void>;
+}
+
+interface ToolResultContent {
+  type: string;
+  text?: string;
+}
+
+function parseSpecFromToolResult(result: {
+  content?: ToolResultContent[];
+}): Spec | null {
+  const textContent = result.content?.find(
+    (c: ToolResultContent) => c.type === "text",
+  );
+  if (!textContent?.text) return null;
+  try {
+    const parsed = JSON.parse(textContent.text);
+    if (parsed && typeof parsed === "object" && "spec" in parsed) {
+      return parsed.spec as Spec;
+    }
+    return parsed as Spec;
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * React hook that connects to the MCP host, listens for tool results,
+ * and maintains the current json-render spec.
+ *
+ * Follows the official MCP Apps pattern: create an `App` instance,
+ * register the `ontoolresult` handler, then call `app.connect()`
+ * which internally creates a PostMessageTransport to the host.
+ */
+export function useJsonRenderApp(
+  options: UseJsonRenderAppOptions = {},
+): UseJsonRenderAppReturn {
+  const { name = "json-render", version = "1.0.0" } = options;
+
+  const [spec, setSpec] = useState<Spec | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [connected, setConnected] = useState(false);
+  const [error, setError] = useState<Error | null>(null);
+  const appRef = useRef<App | null>(null);
+
+  useEffect(() => {
+    const app = new App({ name, version });
+    appRef.current = app;
+
+    app.ontoolresult = (result: { content?: ToolResultContent[] }) => {
+      const parsed = parseSpecFromToolResult(result);
+      if (parsed) {
+        setSpec(parsed);
+        setLoading(false);
+      }
+    };
+
+    // Let the App class handle transport creation internally,
+    // matching the official MCP Apps quickstart pattern.
+    app
+      .connect()
+      .then(() => {
+        setConnected(true);
+      })
+      .catch((err: unknown) => {
+        setError(err instanceof Error ? err : new Error(String(err)));
+      });
+
+    return () => {
+      app.close().catch(() => {});
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
+  const callServerTool = useCallback(
+    async (toolName: string, args: Record<string, unknown> = {}) => {
+      if (!appRef.current) return;
+      setLoading(true);
+      try {
+        const result = await appRef.current.callServerTool({
+          name: toolName,
+          arguments: args,
+        });
+        const parsed = parseSpecFromToolResult(result);
+        if (parsed) setSpec(parsed);
+      } finally {
+        setLoading(false);
+      }
+    },
+    [],
+  );
+
+  return {
+    spec,
+    connecting: !connected && !error,
+    connected,
+    error,
+    loading,
+    app: appRef.current,
+    callServerTool,
+  };
+}

packages/mcp/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "@internal/typescript-config/react-library.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src"
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "dist"]
+}

packages/mcp/tsup.config.ts

@@ -0,0 +1,17 @@
+import { defineConfig } from "tsup";
+
+export default defineConfig({
+  entry: ["src/index.ts", "src/app.ts"],
+  format: ["cjs", "esm"],
+  dts: true,
+  sourcemap: true,
+  clean: true,
+  external: [
+    "react",
+    "react-dom",
+    "@json-render/core",
+    "@json-render/react",
+    "@modelcontextprotocol/sdk",
+    "@modelcontextprotocol/ext-apps",
+  ],
+});

packages/react-email/CHANGELOG.md

@@ -0,0 +1,20 @@
+# @json-render/react-email
+
+## 0.12.0
+
+### Minor Changes
+
+- 63c339b: Add Svelte renderer, React Email renderer, and MCP Apps integration.
+
+  ### New:
+  - **`@json-render/svelte`** — Svelte 5 renderer with runes-based reactivity. Full support for data binding, visibility, actions, validation, watchers, streaming, and repeat scopes. Includes `defineRegistry`, `Renderer`, `schema`, composables, and context providers.
+  - **`@json-render/react-email`** — React Email renderer for generating HTML and plain-text emails from JSON specs. 17 standard components (Html, Head, Body, Container, Section, Row, Column, Heading, Text, Link, Button, Image, Hr, Preview, Markdown). Server-side `renderToHtml` / `renderToPlainText` APIs. Custom catalog and registry support.
+  - **`@json-render/mcp`** — MCP Apps integration that serves json-render UIs as interactive apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients. `createMcpApp` server factory, `useJsonRenderApp` React hook for iframes, and `buildAppHtml` utility.
+
+  ### Fixed:
+  - **`@json-render/svelte`** — Corrected JSDoc comment and added missing `zod` peer dependency.
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0

packages/react-email/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/react-email",
-  "version": "0.8.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "React Email renderer for @json-render/core. JSON becomes HTML emails.",
   "keywords": [

packages/react-native/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/react-native
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/react-native/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/react-native",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "React Native renderer for @json-render/core. JSON becomes React Native components.",
   "keywords": [

packages/react-pdf/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/react-pdf
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/react-pdf/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/react-pdf",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "React PDF renderer for @json-render/core. JSON becomes PDF documents.",
   "keywords": [

packages/react-state/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @internal/react-state
 
+## 0.8.5
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.8.4
 
 ### Patch Changes

packages/react-state/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@internal/react-state",
-  "version": "0.8.4",
+  "version": "0.8.5",
   "private": true,
   "license": "Apache-2.0",
   "description": "Shared React state context for json-render renderer packages",

packages/react/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/react
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/react/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/react",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "React renderer for @json-render/core. JSON becomes React components.",
   "keywords": [

packages/redux/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/redux
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/redux/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/redux",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Redux adapter for json-render StateStore",
   "keywords": [

packages/remotion/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/remotion
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/remotion/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/remotion",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Remotion renderer for @json-render/core. JSON becomes video compositions.",
   "keywords": [

packages/shadcn/CHANGELOG.md

@@ -1,5 +1,13 @@
 # @json-render/shadcn
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+  - @json-render/react@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/shadcn/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/shadcn",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "shadcn/ui component library for @json-render/core. JSON becomes beautiful Tailwind-styled React components.",
   "keywords": [

packages/svelte/CHANGELOG.md

@@ -0,0 +1,20 @@
+# @json-render/svelte
+
+## 0.12.0
+
+### Minor Changes
+
+- 63c339b: Add Svelte renderer, React Email renderer, and MCP Apps integration.
+
+  ### New:
+  - **`@json-render/svelte`** — Svelte 5 renderer with runes-based reactivity. Full support for data binding, visibility, actions, validation, watchers, streaming, and repeat scopes. Includes `defineRegistry`, `Renderer`, `schema`, composables, and context providers.
+  - **`@json-render/react-email`** — React Email renderer for generating HTML and plain-text emails from JSON specs. 17 standard components (Html, Head, Body, Container, Section, Row, Column, Heading, Text, Link, Button, Image, Hr, Preview, Markdown). Server-side `renderToHtml` / `renderToPlainText` APIs. Custom catalog and registry support.
+  - **`@json-render/mcp`** — MCP Apps integration that serves json-render UIs as interactive apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients. `createMcpApp` server factory, `useJsonRenderApp` React hook for iframes, and `buildAppHtml` utility.
+
+  ### Fixed:
+  - **`@json-render/svelte`** — Corrected JSDoc comment and added missing `zod` peer dependency.
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0

packages/svelte/README.md

@@ -0,0 +1,155 @@
+# @json-render/svelte
+
+Svelte 5 renderer for `@json-render/core`. Turn JSON specs into Svelte components with runes-based reactivity.
+
+## Installation
+
+```bash
+npm install @json-render/core @json-render/svelte
+```
+
+Peer dependencies: `svelte ^5.0.0` and `zod ^4.0.0`.
+
+## Quick Start
+
+### 1. Create a Catalog
+
+```typescript
+import { defineCatalog } from "@json-render/core";
+import { schema } from "@json-render/svelte/schema";
+import { z } from "zod";
+
+export const catalog = defineCatalog(schema, {
+  components: {
+    Card: {
+      props: z.object({
+        title: z.string(),
+        description: z.string().nullable(),
+      }),
+      description: "A card container",
+    },
+    Button: {
+      props: z.object({
+        label: z.string(),
+        action: z.string(),
+      }),
+      description: "A clickable button",
+    },
+  },
+  actions: {
+    submit: { description: "Submit the form" },
+  },
+});
+```
+
+### 2. Define Component Implementations
+
+```typescript
+import { defineRegistry } from "@json-render/svelte";
+import { catalog } from "./catalog";
+
+export const { registry } = defineRegistry(catalog, {
+  components: {
+    Card: ({ props, children }) => /* Svelte 5 snippet */,
+    Button: ({ props, emit }) => /* Svelte 5 snippet */,
+  },
+  actions: {
+    submit: async (params) => { /* handle submit */ },
+  },
+});
+```
+
+### 3. Render Specs
+
+```svelte
+<script>
+  import { Renderer, StateProvider, ActionProvider } from "@json-render/svelte";
+  import { registry } from "./registry";
+
+  const spec = { /* ... */ };
+</script>
+
+<StateProvider initialState={{ form: { name: "" } }}>
+  <ActionProvider handlers={{ submit: handleSubmit }}>
+    <Renderer {spec} {registry} />
+  </ActionProvider>
+</StateProvider>
+```
+
+## Providers
+
+| Provider | Purpose |
+|----------|---------|
+| `StateProvider` | Share state across components (JSON Pointer paths). Accepts optional `store` prop for controlled mode. |
+| `ActionProvider` | Handle actions dispatched via the event system |
+| `VisibilityProvider` | Enable conditional rendering based on state |
+| `ValidationProvider` | Form field validation |
+| `RepeatScopeProvider` | Repeat scope for list rendering |
+| `FunctionsContextProvider` | Register `$computed` functions |
+| `JsonUIProvider` | All-in-one provider combining state, actions, visibility, validation, and functions |
+
+## Context Accessors
+
+Svelte 5 uses `getContext`-based accessors instead of hooks:
+
+| Accessor | Purpose |
+|----------|---------|
+| `getStateContext()` | Access state context (`state`, `get`, `set`) |
+| `getStateValue(path)` | Get single value from state |
+| `getBoundProp(value, binding)` | Two-way binding for `$bindState`/`$bindItem` |
+| `getVisibilityContext()` | Access visibility context |
+| `isVisible(condition)` | Check if a visibility condition is met |
+| `getActionContext()` | Access action context |
+| `getAction(binding)` | Get a single action dispatch function |
+| `getValidationContext()` | Access validation context |
+| `getFieldValidation(path, config)` | Field validation state |
+| `getRepeatScope()` | Access current repeat scope |
+| `getFunctions()` | Access registered computed functions |
+
+## Streaming
+
+```typescript
+import { createUIStream, createChatUI } from "@json-render/svelte";
+
+const stream = createUIStream({ endpoint: "/api/generate" });
+
+// Or for chat-style UI:
+const chat = createChatUI({ endpoint: "/api/chat" });
+```
+
+## Key Exports
+
+| Export | Purpose |
+|--------|---------|
+| `defineRegistry` | Create a type-safe component registry from a catalog |
+| `createRenderer` | Create a renderer function from a registry |
+| `Renderer` | Render a spec using a registry |
+| `CatalogRenderer` | Render with automatic provider wiring |
+| `JsonUIProvider` | All-in-one provider |
+| `schema` | Element tree schema (includes built-in state actions) |
+| `createUIStream` | Stream specs from an API endpoint |
+| `createChatUI` | Chat-style streaming interface |
+| `flatToTree` | Convert flat spec to tree format |
+| `ConfirmDialog` | Confirmation dialog component |
+| `ConfirmDialogManager` | Manage multiple confirmation dialogs |
+
+### Types
+
+| Export | Purpose |
+|--------|---------|
+| `ComponentContext` | Typed component render function context (catalog-aware) |
+| `BaseComponentProps` | Catalog-agnostic base type for reusable component libraries |
+| `EventHandle` | Event handle with `emit()`, `shouldPreventDefault`, `bound` |
+| `ComponentFn` | Component render function type |
+| `SetState` | State setter type |
+| `StateModel` | State model type |
+| `SvelteSchema` | Schema type for the Svelte renderer |
+| `SvelteSpec` | Spec type for the Svelte renderer |
+
+## Documentation
+
+Full API reference: [json-render.dev/docs/api/svelte](https://json-render.dev/docs/api/svelte).
+
+## License
+
+Apache-2.0

packages/svelte/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/svelte",
-  "version": "0.6.1",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Svelte 5 renderer for @json-render/core. JSON becomes Svelte components.",
   "keywords": [
@@ -65,6 +65,7 @@
     "typescript": "^5.4.5"
   },
   "peerDependencies": {
-    "svelte": "^5.0.0"
+    "svelte": "^5.0.0",
+    "zod": "^4.0.0"
   }
 }

packages/svelte/src/JsonUIProvider.svelte

@@ -4,8 +4,8 @@
    * Props for JSONUIProvider
    */
   export interface JSONUIProviderProps {
-    /** Component registry */
+    /** Component registry (passed through for convenience; not used internally) */
-    registry: ComponentRegistry;
+    registry?: ComponentRegistry;
     /**
      * External store (controlled mode). When provided, `initialState` and
      * `onStateChange` are ignored.

packages/svelte/src/renderer.ts

@@ -211,7 +211,7 @@ export interface CreateRendererProps {
 }
 
 /**
- * Component map type — maps component names to Vue components
+ * Component map type — maps component names to Svelte components
  */
 export type ComponentMap<
   TComponents extends Record<string, { props: unknown }>,

packages/vue/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/vue
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/vue/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/vue",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Vue renderer for @json-render/core. JSON becomes Vue components.",
   "keywords": [

packages/xstate/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/xstate
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/xstate/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/xstate",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "XState Store adapter for json-render StateStore",
   "keywords": [

packages/zustand/CHANGELOG.md

@@ -1,5 +1,12 @@
 # @json-render/zustand
 
+## 0.12.0
+
+### Patch Changes
+
+- Updated dependencies [63c339b]
+  - @json-render/core@0.12.0
+
 ## 0.11.0
 
 ### Patch Changes

packages/zustand/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@json-render/zustand",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "license": "Apache-2.0",
   "description": "Zustand adapter for json-render StateStore",
   "keywords": [