mcp
MCP Apps integration for json-render. Use when building MCP servers that render interactive UIs in Claude, ChatGPT, Cursor, or VS Code, or when integrating json-render with the Model Context Protocol.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/vercel-labs/json-render --skill mcp- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads mcp automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
Security audits
Independent scans of the skill's instructions and bundled files.
SKILL.md
The instructions your agent reads when the skill is triggered.
@json-render/mcp
MCP Apps integration that serves json-render UIs as interactive MCP Apps inside Claude, ChatGPT, Cursor, VS Code, and other MCP-capable clients.
Quick Start
Server (Node.js)
import { createMcpApp } from "@json-render/mcp";
import { defineCatalog } from "@json-render/core";
import { schema } from "@json-render/react/schema";
import { shadcnComponentDefinitions } from "@json-render/shadcn/catalog";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import fs from "node:fs";
const catalog = defineCatalog(schema, {
components: { ...shadcnComponentDefinitions },
actions: {},
});
const server = createMcpApp({
name: "My App",
version: "1.0.0",
catalog,
html: fs.readFileSync("dist/index.html", "utf-8"),
});
await server.connect(new StdioServerTransport());
Client (React, inside iframe)
import { useJsonRenderApp } from "@json-render/mcp/app";
import { JSONUIProvider, Renderer } from "@json-render/react";
function McpAppView({ registry }) {
const { spec, loading, error } = useJsonRenderApp();
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>
);
}
Architecture
createMcpApp()creates anMcpServerthat registers arender-uitool and aui://HTML resource- The tool description includes the catalog prompt so the LLM knows how to generate valid specs
- The HTML resource is a Vite-bundled single-file React app with json-render renderers
- Inside the iframe,
useJsonRenderApp()connects to the host viapostMessageand renders specs
Server API
createMcpApp(options)- main entry, creates a full MCP serverregisterJsonRenderTool(server, options)- register a json-render tool on an existing serverregisterJsonRenderResource(server, options)- register the UI resource
Client API (@json-render/mcp/app)
useJsonRenderApp(options?)- React hook, returns{ spec, loading, connected, error, callServerTool }buildAppHtml(options)- generate HTML from bundled JS/CSS
Building the iframe HTML
Bundle the React app into a single self-contained HTML file using Vite + vite-plugin-singlefile:
// vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import { viteSingleFile } from "vite-plugin-singlefile";
export default defineConfig({
plugins: [react(), viteSingleFile()],
build: { outDir: "dist" },
});
Client Configuration
Cursor (.cursor/mcp.json)
{
"mcpServers": {
"my-app": {
"command": "npx",
"args": ["tsx", "server.ts", "--stdio"]
}
}
}
Claude Desktop
{
"mcpServers": {
"my-app": {
"command": "npx",
"args": ["tsx", "/path/to/server.ts", "--stdio"]
}
}
}
Dependencies
# Server
npm install @json-render/mcp @json-render/core @modelcontextprotocol/sdk
# Client (iframe)
npm install @json-render/react @json-render/shadcn react react-dom
# Build tools
npm install -D vite @vitejs/plugin-react vite-plugin-singlefile
FAQ
What does the mcp skill do?
MCP Apps integration for json-render. Use when building MCP servers that render interactive UIs in Claude, ChatGPT, Cursor, or VS Code, or when integrating json-render with the Model Context Protocol.
How do I install mcp?
Run npx skills add https://github.com/vercel-labs/json-render --skill mcp in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/mcp/ (personal) or .claude/skills/mcp/ (project).
Which AI agents can use mcp?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is mcp safe to install?
Security partners have reviewed it: Gen Agent Trust Hub passed; Socket passed; Snyk passed; Runlayer passed; ZeroLeaks passed. As with any skill, read the SKILL.md and bundled scripts before installing.
Who maintains mcp?
It is published by vercel-labs in vercel-labs/json-render, and it is an official skill from the maker of the technology it covers. It has 5,845 recorded installs.
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