`create_checkout`

Start and price a checkout for one product or session.

Anonymous, or a Bearer token for viewer tools

Endpoint

endpoint

https://go.sessions.website/@<handle>/api/ucp/mcp

When to use it

To buy on someone’s behalf from a server-side agent — this is the surface that can actually take payment, unlike Web MCP.
For one product (pass, membership, gift card, merchandise) or one session registration per checkout.

Parameters

checkoutobjectrequired

A partial UCP checkout object. line_items takes exactly one entry, whose item.id is a Sessions global id (a product or a scheduled session).

metaobjectoptional

Request metadata: {"ucp-agent": "<your platform profile URI>", "idempotency-key": "<uuid>"}.

Returns

The checkout session with its id, status, priced totals, and any messages — including requires_escalation with a continue_url when something (a waiver, a membership consent, 3-D Secure) can only be finished by a person.

Example

POST this to the endpoint above.

JSON-RPC

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create_checkout",
    "arguments": {
      "checkout": {
        "line_items": [
          {
            "item": {
              "id": "<product or session id>"
            }
          }
        ]
      },
      "meta": {
        "ucp-agent": "https://your-platform.example/profile"
      }
    }
  }
}

content

checkout_abc123 · status: ready_for_payment
Subtotal: $24.00 · Tax: $0.00 · Total: $24.00

What the agent is told

The description the model reads when deciding whether to call this. It is the only thing that decides whether the tool fires at the right moment, so it is worth knowing what it says.

create_checkout

Start a UCP checkout for one Sessions product (pass, membership, gift card, physical product) or one scheduled session registration. Prices the item, applies any discount or gift-card code, and returns the checkout session with its totals and status.