# Step 8 — ACP, AP2, MPP

Three commerce surfaces: /.well-known/acp.json (protocol, api_base_url, transports, and capabilities.services as a flat ID array), the AP2 extension declared on the A2A card, and MPP x-payment-info metadata inside your OpenAPI document. Each is a different buyer’s preferred rail.

Canonical: https://robauto.ai/learn/advanced-agentic-commerce/10

_Advanced Agentic Commerce: Ship the Full Agent Surface — lesson 10 of 20 (DEFINITION)_

Three commerce surfaces: /.well-known/acp.json (protocol, api_base_url, transports, and capabilities.services as a flat ID array), the AP2 extension declared on the A2A card, and MPP x-payment-info metadata inside your OpenAPI document. Each is a different buyer’s preferred rail.

Source: [Agentic Commerce Protocol](https://www.agenticcommerce.dev?utm_source=robauto)

[Previous lesson](/learn/advanced-agentic-commerce/9) · [Next lesson](/learn/advanced-agentic-commerce/11) · [Course overview](/learn/advanced-agentic-commerce) · [All courses](/learn)

---

(c) 2026 Robauto, Inc. — support@robauto.ai
Machine surfaces: https://robauto.ai/llms.txt · https://robauto.ai/llms-full.txt · https://robauto.ai/.well-known/api-catalog