Official Docs

OpenAI ChatGPT Apps SDK

Official SDK for building ChatGPT Apps with MCP, tools, and UI widgets.

Overview

The Apps SDK is the foundation for building ChatGPT applications. It provides MCP server setup, tool definitions, and UI component templates that render inline within ChatGPT. The SDK supports both Python and TypeScript implementations, with FastMCP for rapid prototyping and @modelcontextprotocol/sdk for Node/React stacks.

Key Points

MCP server exposes tools that ChatGPT can call with structured data

Each tool must reference an HTML UI template for rendering

Supports Python SDK (official) and TypeScript SDK (official)

Tools require clear machine names, human-friendly titles, and JSON schemas

UI templates are registered as resources with mimeType text/html+skybridge

Version carefully when shipping breaking component changes

Prerequisites

Basic understanding of MCP (Model Context Protocol)

Python or TypeScript/Node.js knowledge

Web framework experience (FastAPI or Express recommended)

Step-by-Step Guide

1Choose and install the appropriate SDK (Python or TypeScript)

2Set up your web framework (FastAPI or Express)

3Define tools with clear schemas and metadata

4Create HTML UI templates for your components

5Register templates as resources with proper mimeType

6Link tools to templates using _meta["openai/outputTemplate"]