MCP Apps vs OpenAI Apps SDK: are they competing standards?

MCP Apps 与 OpenAI Apps SDK：它们是竞争标准吗？

If you have started building tools for AI chat hosts, you have probably hit the same fork in the road. There are two ways to add a user interface to a tool right now. The first is MCP Apps, the open standard from the Model Context Protocol. The second is the OpenAI Apps SDK, the framework OpenAI shipped for the ChatGPT app store. 如果你已经开始为 AI 聊天主机构建工具，你可能已经遇到了同样的岔路口。目前有两种为工具添加用户界面的方法。第一种是 MCP Apps，即来自模型上下文协议（Model Context Protocol）的开放标准；第二种是 OpenAI Apps SDK，这是 OpenAI 为 ChatGPT 应用商店推出的框架。

They both let your tool render a UI inside the chat. They both run inside a sandboxed iframe. They both talk to your server over JSON-RPC. So the question almost every developer is asking is the obvious one: are these competing standards? 它们都允许你的工具在聊天界面内渲染 UI，都在沙盒 iframe 中运行，并且都通过 JSON-RPC 与你的服务器通信。因此，几乎每个开发者都在问一个显而易见的问题：它们是竞争标准吗？

The short answer: No. The OpenAI Apps SDK is built on top of MCP. It uses MCP for the wire format, the tool definitions, the UI rendering, and the security model. It then adds a thin layer with ChatGPT-specific extensions: a payment hook (window.openai.requestCheckout), a store directory, and a few helpers that only run inside ChatGPT. 简短的回答是：不是。OpenAI Apps SDK 是构建在 MCP 之上的。它使用 MCP 进行传输格式、工具定义、UI 渲染和安全模型设计。在此基础上，它增加了一个轻量层，包含 ChatGPT 特有的扩展：支付钩子（window.openai.requestCheckout）、商店目录，以及一些仅在 ChatGPT 内部运行的辅助工具。

So the choice is not “pick one or the other.” The honest framing is: Build to MCP Apps first. Your tool then works in Claude, Claude Desktop, VS Code, Goose, Postman, MCPJam, and any host that supports the open standard. Light up OpenAI Apps SDK extensions only when you need ChatGPT-specific features. Mostly that means payments and the ChatGPT app store. 所以，选择并不是“二选一”。更客观的说法是：优先构建 MCP Apps。这样你的工具就可以在 Claude、Claude Desktop、VS Code、Goose、Postman、MCPJam 以及任何支持该开放标准的主机中运行。只有当你需要 ChatGPT 特有功能时，才启用 OpenAI Apps SDK 扩展。这通常意味着支付功能和 ChatGPT 应用商店。

The four real differences: Strip away the marketing and there are only four things the OpenAI Apps SDK gives you that MCP Apps do not: 真正的四个区别：剥离营销术语，OpenAI Apps SDK 相比 MCP Apps 只提供了四样东西：

A store and a directory — the ChatGPT app store will list your app and surface it to ChatGPT users. The open MCP spec has no centralised discovery.
商店和目录 —— ChatGPT 应用商店会列出你的应用并将其展示给 ChatGPT 用户。而开放的 MCP 规范没有中心化的发现机制。
In-chat payments — window.openai.requestCheckout() runs a payment flow without leaving the chat. MCP Apps has no checkout primitive today.
聊天内支付 —— window.openai.requestCheckout() 可以在不离开聊天界面的情况下运行支付流程。MCP Apps 目前没有结账原语。
Conversation-aware helpers — tighter access to surrounding conversation state.
对话感知辅助工具 —— 对周围对话状态有更紧密的访问权限。
Distribution to ChatGPT users specifically — ChatGPT has hundreds of millions of users; the Apps SDK is the only way to reach them through OpenAI’s surface.
专门针对 ChatGPT 用户的分发 —— ChatGPT 拥有数亿用户；Apps SDK 是通过 OpenAI 界面触达这些用户的唯一途径。

Everything else — the sandboxing, the iframe rendering, the JSON-RPC audit trail, the tool declarations — is the same on both sides because the Apps SDK uses MCP for them. 其他所有内容——沙盒、iframe 渲染、JSON-RPC 审计追踪、工具声明——在两者中都是相同的，因为 Apps SDK 在这些方面使用了 MCP。

Which one to pick: If your audience is ChatGPT users specifically and you need in-chat payments, build with the OpenAI Apps SDK. For everyone else, build to MCP Apps and your tool runs across every host that supports the open standard. 如何选择：如果你的目标受众专门是 ChatGPT 用户且你需要聊天内支付功能，请使用 OpenAI Apps SDK 构建。对于其他所有人，请构建 MCP Apps，这样你的工具就能在所有支持该开放标准的主机上运行。

I wrote the full comparison — code examples for both sides, the smart progressive-enhancement pattern, a decision tree, and the two pitfalls most teams hit — on my blog. Read the full guide on moeed.app → 我在我的博客上撰写了完整的对比分析，包括双方的代码示例、智能渐进增强模式、决策树以及大多数团队会遇到的两个陷阱。请在 moeed.app 阅读完整指南 →