ACP Checkout — MCP Binding

Before writing code

Fetch live docs:

1. Fetch https://github.com/agentic-commerce-protocol/agentic-commerce-protocol/releases for the current spec version.
2. Fetch the official OpenRPC document — spec/<version>/openrpc/openrpc.agentic_checkout.json in the repo. Since the 2026-04-17 release there is a machine-readable JSON-RPC description of the checkout binding; use it rather than hand-deriving tool names. The table below predates it.
3. Fetch https://developers.openai.com/commerce/specs/checkout/ for checkout operation semantics.
4. Fetch https://modelcontextprotocol.io/specification/ — it redirects to the current MCP revision. Confirm the transport model before writing server code; MCP's core changed shape between revisions (the stateless core removed the initialize handshake and Mcp-Session-Id), so a server written against an older revision will not match a current client.
5. Fetch MCP SDK docs: web-search site:github.com modelcontextprotocol python-sdk or typescript-sdk for the current SDK.

Conceptual Architecture

What MCP Binding Means

ACP's REST checkout operations can be exposed as MCP tools via an MCP server. This allows AI agents that use tool-calling (Claude, ChatGPT, Gemini) to invoke checkout operations directly as tools rather than making raw HTTP calls.

Since 2026-04-17 this mapping is specified, not improvised — the OpenRPC document is the source of truth for method names and parameter shapes. Treat the mapping below as orientation and the OpenRPC document as normative.