There is a lot of talk about Agentic Commerce, but most of it is still hand-wavy.
If you build, test or optimise eCommerce systems, you will want to see how these new protocols actually talk to each other.
Here is a simple example of what the two key formats look like:
This is what an ACP product capability document might look like from a merchant’s side.
It tells the AI agent what products you sell, where to fetch live pricing, and how to create an order.
In short:
- `capabilities` tells the agent how to interact with your site
- `catalogue` is your live structured data of products
- `constraints` outlines spend caps, delivery areas and allowed payment types
AP2 handles the buyer side.
It defines how an AI agent gets permission from the user to complete a transaction securely and provably.
Here is an example Cart Mandate payload an AI might send to your checkout endpoint:
This tells your system:
- The user has approved a purchase up to £650
- The AI (acting as agent) is authorised to submit this specific cart
- You can verify the signature against the user’s stored payment credentials
1. The AI discovers your ACP feed and learns what you sell.
2. The user gives consent through AP2 and the AI signs a Mandate.
3. Your backend validates the mandate and processes the order.
4. Payment networks (Stripe, Visa, etc.) verify the signature and settle funds.
The merchant never loses control, you stay merchant of record.
The buyer never loses protection, they have a verifiable digital consent trail.
For developers:
You can start designing your feeds around this structure today. It is mostly JSON over HTTPS and fits neatly with your current API stack.
For store owners:
ACP and AP2 are not just buzzwords. They will decide whether your products can be seen, bought or recommended by AI agents next year.
Try out my new AP2 (Agent Payments Protocol) Builder Tool: https://chrisleverseo.com/tools/ap2-feed-builder-tool/
If you build, test or optimise eCommerce systems, you will want to see how these new protocols actually talk to each other.
Here is a simple example of what the two key formats look like:
ACP — Agentic Commerce Protocol (Merchant Feed Example)
This is what an ACP product capability document might look like from a merchant’s side.
It tells the AI agent what products you sell, where to fetch live pricing, and how to create an order.
Code:
{
"merchant": {
"id": "example-store-uk",
"name": "Example Store",
"domain": "https://example-store.co.uk",
"currency": "GBP"
},
"capabilities": {
"list_products": "https://example-store.co.uk/api/acp/products",
"get_price": "https://example-store.co.uk/api/acp/price",
"get_shipping": "https://example-store.co.uk/api/acp/shipping",
"create_order": "https://example-store.co.uk/api/acp/orders"
},
"catalogue": [
{
"sku": "SOFA-LINEN-GRY-3S",
"title": "3-Seater Linen Sofa in Grey",
"description": "Hardwearing grey linen sofa with solid oak legs. Delivered in 3–5 days across the UK.",
"price": 599.00,
"in_stock": true,
"delivery_zones": ["UK"],
"images": [
"https://example-store.co.uk/images/sofa-grey-1.webp",
"https://example-store.co.uk/images/sofa-grey-2.webp"
],
"meta": {
"brand": "Stable Home",
"category": "Living Room",
"rating": 4.8
}
}
],
"constraints": {
"max_order_value_gbp": 2000.00,
"allowed_payment_methods": ["card", "apple_pay"]
}
}In short:
- `capabilities` tells the agent how to interact with your site
- `catalogue` is your live structured data of products
- `constraints` outlines spend caps, delivery areas and allowed payment types
AP2 — Agent Payments Protocol (User Mandate Example)
AP2 handles the buyer side.
It defines how an AI agent gets permission from the user to complete a transaction securely and provably.
Here is an example Cart Mandate payload an AI might send to your checkout endpoint:
Code:
{
"mandate_type": "cart",
"mandate_id": "mandate-99821",
"user_id": "user-54321",
"agent_id": "chatgpt-001",
"cart": {
"merchant": "example-store-uk",
"items": [
{
"sku": "SOFA-LINEN-GRY-3S",
"quantity": 1,
"price": 599.00
}
],
"currency": "GBP",
"subtotal": 599.00,
"delivery": 30.00,
"total": 629.00
},
"constraints": {
"spend_limit_gbp": 650.00,
"expires_at": "2025-10-11T18:00:00Z"
},
"user_consent": {
"timestamp": "2025-10-04T17:12:45Z",
"signature": "base64-ed25519-signature"
}
}This tells your system:
- The user has approved a purchase up to £650
- The AI (acting as agent) is authorised to submit this specific cart
- You can verify the signature against the user’s stored payment credentials
How They Fit Together
1. The AI discovers your ACP feed and learns what you sell.
2. The user gives consent through AP2 and the AI signs a Mandate.
3. Your backend validates the mandate and processes the order.
4. Payment networks (Stripe, Visa, etc.) verify the signature and settle funds.
The merchant never loses control, you stay merchant of record.
The buyer never loses protection, they have a verifiable digital consent trail.
Why It Matters
For developers:
You can start designing your feeds around this structure today. It is mostly JSON over HTTPS and fits neatly with your current API stack.
For store owners:
ACP and AP2 are not just buzzwords. They will decide whether your products can be seen, bought or recommended by AI agents next year.
Try out my new AP2 (Agent Payments Protocol) Builder Tool: https://chrisleverseo.com/tools/ap2-feed-builder-tool/