Product checkout conversion spec

Purpose

Our goal is to let ChatGPT directly invoke partner plugins for high-intent use cases such as product checkout.

Once partners provide us with a product feed for search, we can connect their MCP servers for bottom-of-funnel conversion actions. To do this, partner plugins must follow a standardized contract for widget name, tool name, and tool input.

If you want to build a plugin that follows this spec, apply for access through the ChatGPT merchants form.

User experience

When users search for products, the product entity sidebar can show Open buttons for sellers. If a seller has a plugin, ChatGPT can open that plugin inline for checkout instead of punching out to an external website.

Required contract (today)

• Widget name: ui://widget/checkout-session.html
• Tool name: checkout_session

checkout_session must set:

_meta.ui.resourceUri = "ui://widget/checkout-session.html";

Any tool called directly from a widget must set:

_meta["openai/widgetAccessible"] = true;

checkout_session input

Current input shape:

{
  "checkout_session": {
    "items": [
      {
        "id": "string",
        "quantity": 1,
        "offerId": "string"
      }
    ]
  }
}

This payload aligns with the Commerce checkout session shape documented here.