Update READMEs with MCP server setup and stdio transport docs

- Add MCP Server section to root README with Claude Desktop and
  Claude Code setup instructions
- Update apps/mcp README with stdio usage for Claude Desktop
- Update project structure to include stdio.ts entry point

Author: GeneralJerel

README.md

@@ -42,14 +42,60 @@ make dev      # Start all services
 
 You can also use `pnpm` directly (`pnpm dev`, `pnpm dev:app`, `pnpm dev:agent`, etc.).
 
+## MCP Server (Self-Hosted)
+
+The repo includes a standalone [Model Context Protocol](https://modelcontextprotocol.io) server that exposes the design system, skill instructions, and an HTML document assembler to any MCP-compatible client — including Claude Desktop, Claude Code, and Cursor.
+
+### What it provides
+
+- **`assemble_document` tool** — wraps HTML fragments with the full design system CSS and bridge JS, returning an iframe-ready document
+- **Skill resources** — browse and read skill instruction documents (`skills://list`, `skills://{name}`)
+- **Prompt templates** — pre-composed prompts for widgets, SVG diagrams, and advanced visualizations
+
+### Claude Desktop (stdio)
+
+Add to your Claude Desktop config (`claude_desktop_config.json`):
+
+```json
+{
+  "mcpServers": {
+    "open-generative-ui": {
+      "command": "node",
+      "args": ["dist/stdio.js"],
+      "cwd": "/path/to/apps/mcp"
+    }
+  }
+}
+```
+
+### Claude Code / HTTP clients
+
+```bash
+# Start the HTTP server
+cd apps/mcp && pnpm dev
+```
+
+Add to `.mcp.json`:
+
+```json
+{
+  "openGenerativeUI": {
+    "url": "http://localhost:3100/mcp"
+  }
+}
+```
+
+See [apps/mcp/README.md](apps/mcp/README.md) for full configuration, Docker deployment, and API reference.
+
 ## Architecture
 
-Turborepo monorepo with two apps:
+Turborepo monorepo with three packages:
 
 ```
 apps/
 ├── app/       Next.js 16 frontend (CopilotKit v2, React 19, Tailwind 4)
-└── agent/     LangGraph Python agent (GPT-5.4, CopilotKit middleware)
+├── agent/     LangGraph Python agent (GPT-5.4, CopilotKit middleware)
+└── mcp/       Standalone MCP server (design system + skills + document assembler)
 ```
 
 ### How It Works

apps/mcp/README.md

@@ -61,7 +61,41 @@ LOG_LEVEL=info
 
 ## Usage
 
-### From Claude Code
+### Claude Desktop (stdio)
+
+Claude Desktop uses stdio transport. Build first, then add to your `claude_desktop_config.json`:
+
+```bash
+pnpm build
+```
+
+```json
+{
+  "mcpServers": {
+    "open-generative-ui": {
+      "command": "node",
+      "args": ["dist/stdio.js"],
+      "cwd": "/absolute/path/to/apps/mcp"
+    }
+  }
+}
+```
+
+For development, you can use `tsx` directly:
+
+```json
+{
+  "mcpServers": {
+    "open-generative-ui": {
+      "command": "npx",
+      "args": ["tsx", "src/stdio.ts"],
+      "cwd": "/absolute/path/to/apps/mcp"
+    }
+  }
+}
+```
+
+### Claude Code (HTTP)
 
 Add to `.mcp.json`:
 
@@ -73,11 +107,12 @@ Add to `.mcp.json`:
 }
 ```
 
-Then use the available tools and resources in Claude conversations.
+Then start the HTTP server with `pnpm dev`.
 
-### From Any MCP Client
+### Any MCP Client
 
-Connect via HTTP MCP transport to `http://localhost:3100/mcp`.
+- **stdio**: Run `node dist/stdio.js` (or `pnpm start:stdio`)
+- **HTTP**: Connect to `http://localhost:3100/mcp` (start with `pnpm dev` or `pnpm start`)
 
 ## API Reference
 
@@ -224,8 +259,9 @@ apps/mcp/
 ├── Dockerfile           # Container definition
 ├── skills/              # Skill instruction files (copied from source)
 └── src/
-    ├── index.ts         # Hono HTTP server entry point
-    ├── server.ts        # MCP server construction
+    ├── index.ts         # HTTP server entry point (Hono)
+    ├── stdio.ts         # stdio transport entry point (Claude Desktop)
+    ├── server.ts        # MCP server construction (shared)
     ├── skills.ts        # Skill file loader
     └── renderer.ts      # Design system CSS + assembleDocument
 ```