decentralegends.com

{
    "ucp": {
        "version": "2026-01-23",
        "merchant": {
            "name": "Decentra Legends",
            "website": "https://decentralegends.com",
            "logo_url": "https://decentralegends.com/images/catalog/replica-jersey.jpg",
            "description": "An unlicensed concept store with agent catalog, test payment, and checkout flows.",
            "support_email": "[email protected]",
            "primary_domain": "decentralegends.com"
        },
        "services": {
            "dev.ucp.shopping": {
                "a2a": {
                    "spec": "https://ucp.dev/2026-01-23/specification/overview",
                    "version": "2026-01-23",
                    "endpoint": "https://decentralegends.com/.well-known/agent-card.json",
                    "transport": "a2a"
                },
                "rest": {
                    "schema": "https://ucp.dev/services/shopping/rest.openapi.json",
                    "endpoint": "https://decentralegends.com/ucp"
                },
                "spec": "https://ucp.dev/specification/overview/",
                "version": "2026-01-23"
            }
        },
        "capabilities": [
            {
                "name": "dev.ucp.shopping.checkout",
                "spec": "https://ucp.dev/specification/checkout/",
                "schema": "https://ucp.dev/schemas/shopping/checkout.json",
                "version": "2026-01-23"
            },
            {
                "name": "dev.ucp.shopping.order",
                "spec": "https://ucp.dev/specification/order/",
                "schema": "https://ucp.dev/schemas/shopping/order.json",
                "version": "2026-01-23"
            },
            {
                "name": "dev.ucp.shopping.catalog",
                "spec": "https://ucp.dev/specification/catalog/",
                "schema": "https://ucp.dev/schemas/shopping/catalog.json",
                "version": "2026-01-23"
            }
        ]
    },
    "payment": {
        "handlers": [
            {
                "id": "decentra_staging_card",
                "name": "Decentra staging card",
                "spec": "https://github.com/agentic-commerce-protocol/agentic-commerce-protocol/blob/main/rfcs/rfc.payment_handlers.md",
                "config": {
                    "environment": "test",
                    "merchant_id": "merchant_decentra_legends_staging",
                    "config_schema": "https://decentralegends.com/acp/schemas/staging-card-config.json",
                    "accepted_brands": [
                        "visa",
                        "mastercard"
                    ],
                    "completion_bindings": {
                        "acp": {
                            "request_field": "payment_data.instrument",
                            "credential_type": "spt",
                            "completion_route": "https://decentralegends.com/acp/checkout_sessions/{checkout_id}/complete",
                            "instrument_schema": "https://decentralegends.com/acp/schemas/staging-card-instrument.json"
                        },
                        "ucp_a2a": {
                            "action": "complete_checkout",
                            "request_field": "a2a.ucp.checkout.payment",
                            "credential_type": "PAYMENT_GATEWAY",
                            "completion_route": "https://decentralegends.com/a2a/message:send",
                            "instrument_schema": "https://decentralegends.com/ucp/schemas/staging-card-a2a-instrument.json"
                        }
                    },
                    "delegate_payment_url": "https://decentralegends.com/agentic_commerce/delegate_payment"
                },
                "version": "2026-01-30"
            },
            {
                "id": "visa_acceptance_network_token",
                "name": "Visa Acceptance network token",
                "spec": "https://ucp.dev/2026-08-25/schemas/common/types/network_token_credential.json",
                "config": {
                    "processor": "visa_acceptance",
                    "environment": "sandbox",
                    "credential_type": "network_token",
                    "accepted_networks": [
                        "visa"
                    ],
                    "completion_bindings": {
                        "acp": {
                            "request_field": "payment_data.instrument",
                            "credential_type": "network_token",
                            "completion_route": "https://decentralegends.com/acp/checkout_sessions/{checkout_id}/complete",
                            "instrument_schema": "https://decentralegends.com/acp/schemas/visa-network-token-instrument.json"
                        },
                        "ucp_a2a": {
                            "action": "complete_checkout",
                            "request_field": "a2a.ucp.checkout.payment",
                            "credential_type": "network_token",
                            "completion_route": "https://decentralegends.com/a2a/message:send",
                            "instrument_schema": "https://decentralegends.com/ucp/schemas/visa-network-token-a2a-instrument.json"
                        }
                    }
                },
                "version": "2026-08-25"
            }
        ]
    },
    "signing_keys": [],
    "alternate_protocols": {
        "acp": {
            "version": "2026-01-30",
            "endpoint": "https://decentralegends.com/acp/checkout_sessions",
            "product_feed": "https://decentralegends.com/acp/product_feed.jsonl"
        }
    }
}

# Decentra Legends

> Decentra Legends is a fictional sports-merchandise storefront for testing guest carts, exact inventory, human handoff, and agentic commerce. All products, payment credentials, and orders are for demonstration only. No real charge or purchase is approved.

Use the standard UCP discovery profile as the first commerce entry point. The site also supports the standard ACP checkout and delegated-payment paths. Keep the opaque shopping-session token private and send it on later requests for the same cart.

The Storekeeper agent is live through the standard UCP A2A binding. It creates one durable Storekeeper context and one private cart for each agent shopping session. The main interface is A2A 1.0 HTTP+JSON. A narrow A2A 0.3 JSON-RPC interface supports compatible UCP clients. Both interfaces use the same UCP and ACP cart, inventory, staging-payment, order, and handoff authority.

## Commerce discovery

- [UCP discovery profile](https://decentralegends.com/.well-known/ucp): Canonical starting point for supported commerce services and capabilities.
- [Agentic-commerce compatibility discovery](https://decentralegends.com/.well-known/agentic-commerce): Compatibility alias for clients that probe this well-known path. It returns the canonical UCP profile.
- [A2A Agent Card](https://decentralegends.com/.well-known/agent-card.json): Standard A2A interfaces, Storekeeper skill, authentication, and UCP extension.
- [A2A 1.0 Storekeeper](https://decentralegends.com/a2a): Base URL for synchronous HTTP+JSON message and task operations.
- [A2A 0.3 compatibility](https://decentralegends.com/a2a/jsonrpc): Narrow JSON-RPC compatibility endpoint for the same Storekeeper.
- [ACP product feed](https://decentralegends.com/acp/product_feed.jsonl): Exact products, variants, prices, and availability in JSON Lines format.
- [Machine-readable pricing](https://decentralegends.com/pricing.md): Exact prices, shipping, tax, inventory-hold rules, demo-payment rules, and endpoint list.

## UCP A2A request requirements

UCP requires the `UCP-Agent` header to use RFC 8941 Dictionary Structured Field syntax. A syntactically valid demo value is:

`UCP-Agent: profile="https://agent.example/.well-known/ucp"`

Send these required protocol and UCP headers on each A2A 1.0 request:

- `A2A-Version: 1.0`
- `X-A2A-Extensions: https://ucp.dev/2026-01-23/specification/reference`
- `UCP-Agent: profile="https://agent.example/.well-known/ucp"`

Add `Content-Type: application/a2a+json` to each POST request. Send `Accept: application/a2a+json` when the client declares a response media type. After the first valid send, add the required `X-Shopping-Session-Token` header to each later message request and every task request.

Send a new A2A message to `POST https://decentralegends.com/a2a/message:send`. The first valid send returns `X-Shopping-Session-Token`. Keep it private and send it on later messages and task requests. Structured supported requests work without a configured model. Text cannot create payment data.

The Storekeeper supports these deterministic structured action names in a JSON data part. This `action` envelope is a documented demo convenience; UCP checkout data and payment parts still use the pinned UCP schemas.

- `search_catalog`: `query` accepts exact catalog terms or natural shopper wording, plus optional `filters`. Search removes safe shopper filler and normalizes a small set of common merchandise synonyms for candidate discovery. This normalization does not mean that the shopper's original words are exact catalog fields; use explicit filters and the returned fields as the authoritative facts. `availability=in_stock` includes all products with available units, including low-stock products. `max_price` is in dollars, for example `100`. Search returns compact product summaries and option values, but not the full variant list. Each summary includes `signed`, `accepts_returns`, `final_sale`, and `return_deadline_in_days` when returns are accepted. When Bears matches Chicago Bears and California Golden Bears products, the result is input-required and includes grouped `team_candidates`; ask the shopper to choose a team before recommending or adding an item. When combined discovery terms return no product, the result keeps `products` empty and returns clearly labeled per-term `alternatives`.
- `get_product`: `product_id` can be a product ID, base SKU, slug, or public-feed `item_id`. Use it after search to get the full exact variant list and the same signed and return-policy facts.
- `get_cart`: no arguments.
- `add_cart_item`: `product_id` accepts a public-feed `item_id`; also send a positive `quantity`. An optional `product_variant_id` accepts an exact variant ID or SKU. Ask for every option that the shopper did not provide. Never infer or default a size, color, style, or other product option.
- `set_cart_item_quantity`: `line_id` and a non-negative `quantity`.
- `remove_cart_item`: `line_id`.
- `get_or_start_checkout`: no arguments.
- `cancel_checkout`: `checkout_id`.
- `get_order`: `order_number`. A completed order includes a short-lived secure browser receipt URL.
- `create_handoff`: `checkout_id`. The exact result includes a stable non-secret `handoff_id` and a secret browser URL. Exact replay returns the same ID. Read safe status with the current shopping-session token at `GET https://decentralegends.com/ucp/checkout-sessions/<checkout-id>/handoffs/<handoff-id>`.

This server uses `https://decentralegends.com`. The demo applies a fixed shipping estimate and does not collect a delivery address. `ready_for_complete` means that demo inventory is reserved and the simulated checkout can accept its staging payment. It does not mean that real fulfillment data is complete.

This full A2A 1.0 request can be replayed as written. A2A 1.0 uses `ROLE_USER`; lowercase `user` is the older A2A 0.3 value.

```http
POST https://decentralegends.com/a2a/message:send
A2A-Version: 1.0
Content-Type: application/a2a+json
Accept: application/a2a+json
X-A2A-Extensions: https://ucp.dev/2026-01-23/specification/reference
UCP-Agent: profile="https://agent.example/.well-known/ucp"

{"message":{"messageId":"demo-add-001","role":"ROLE_USER","parts":[{"data":{"action":"add_cart_item","product_id":"DL-DAL-TS-V014","quantity":1},"mediaType":"application/json"}]}}
```

## A2A 1.0 task operations

Every task request requires these headers:

- `A2A-Version: 1.0`
- `X-A2A-Extensions: https://ucp.dev/2026-01-23/specification/reference`
- `UCP-Agent: profile="https://agent.example/.well-known/ucp"`
- `X-Shopping-Session-Token: <token returned by the first valid send>`

`Accept: application/a2a+json` is optional. The response media type is `application/a2a+json`. The cancel POST also requires `Content-Type: application/a2a+json` and an empty JSON object, `{}`.

The concrete A2A 1.0 task routes are:

- `GET https://decentralegends.com/a2a/tasks`: List the tasks that belong to the shopping session. All query parameters are optional. `contextId` selects the exact Storekeeper context. `status` accepts `TASK_STATE_SUBMITTED`, `TASK_STATE_WORKING`, `TASK_STATE_COMPLETED`, `TASK_STATE_FAILED`, `TASK_STATE_CANCELED`, `TASK_STATE_INPUT_REQUIRED`, or `TASK_STATE_REJECTED`. `pageSize` accepts `1` through `100` and defaults to `50`. `pageToken` is the opaque `nextPageToken` from the prior page. `historyLength` accepts a non-negative integer. `statusTimestampAfter` accepts an ISO 8601 UTC time and includes tasks updated at that time or later. `includeArtifacts` accepts `true` or `false` and defaults to `false`.
- `GET https://decentralegends.com/a2a/tasks/<task-id>`: Read one durable task. Replace `<task-id>` with the task `id`. This route has no required query parameter and no request body.
- `POST https://decentralegends.com/a2a/tasks/<task-id>:cancel`: Cancel one non-terminal task. Replace `<task-id>` with the task `id` and send `{}`. Cancellation does not cancel the Storekeeper context, cart, or checkout. A completed, failed, canceled, or expired task cannot be canceled.

To resume after a pause, keep the private shopping-session token and either the task `id` or its `contextId`. Read the saved task directly. If only the context is available, list its tasks first. To continue the same Storekeeper context, send a new message with a new `messageId` and the saved `contextId`.

```http
GET https://decentralegends.com/a2a/tasks/<saved-task-id>
A2A-Version: 1.0
Accept: application/a2a+json
X-A2A-Extensions: https://ucp.dev/2026-01-23/specification/reference
UCP-Agent: profile="https://agent.example/.well-known/ucp"
X-Shopping-Session-Token: <saved guest session token>
```

## ACP checkout and payment

- [ACP checkout](https://decentralegends.com/acp/checkout_sessions): Create an isolated guest checkout with `API-Version: 2026-01-30` and an `Idempotency-Key`.
- [ACP delegated payment](https://decentralegends.com/agentic_commerce/delegate_payment): Exchange a scoped synthetic test credential for a single-use staging-payment token. The allowance expiry must be in the future and no more than 600 seconds from the request time.
- [Staging card configuration schema](https://decentralegends.com/acp/schemas/staging-card-config.json): Merchant, environment, and accepted-brand configuration.
- [ACP staging completion instrument schema](https://decentralegends.com/acp/schemas/staging-card-instrument.json): Shape used only in `payment_data.instrument` on an ACP completion route. It requires credential type `spt`.
- [UCP A2A staging completion instrument schema](https://decentralegends.com/ucp/schemas/staging-card-a2a-instrument.json): Shape used only in `a2a.ucp.checkout.payment` on an A2A completion route. It requires credential type `PAYMENT_GATEWAY`.
- [ACP Visa network-token instrument schema](https://decentralegends.com/acp/schemas/visa-network-token-instrument.json): Visa Acceptance sandbox alternative for the normal ACP completion route. It requires credential type `network_token`.
- [UCP A2A Visa network-token instrument schema](https://decentralegends.com/ucp/schemas/visa-network-token-a2a-instrument.json): Visa Acceptance sandbox alternative for the normal `complete_checkout` action. It requires credential type `network_token`.

ACP uses `X-Shopping-Session-Token` to preserve one private guest cart across requests. The internal staging provider accepts only synthetic `tok_` or `pm_` values and contacts no payment provider. The separate Visa Acceptance handler accepts only its advertised Visa network-token instrument and calls the configured Visa Acceptance sandbox. Neither handler accepts a raw-card credential, and no real funds move.

A valid ACP 2026-01-30 checkout-create request is:

```http
POST https://decentralegends.com/acp/checkout_sessions
API-Version: 2026-01-30
Idempotency-Key: unique-request-key
Content-Type: application/json

{"line_items":[{"id":"DL-DAL-TS-V014"}],"currency":"USD","capabilities":{}}
```

The checkout response returns its exact total and `X-Shopping-Session-Token`. Use that total as `max_amount`, use lowercase `usd`, and set `expires_at` to a future ISO 8601 time no more than 600 seconds away. A complete delegated-payment request is:

```http
POST https://decentralegends.com/agentic_commerce/delegate_payment
API-Version: 2026-01-30
Idempotency-Key: unique-payment-key
X-Shopping-Session-Token: <token returned by checkout creation>
Content-Type: application/json

{"payment_method":{"type":"card","card_number_type":"network_token","number":"tok_visa","display_card_funding_type":"credit","display_brand":"visa","display_last4":"4242","metadata":{"environment":"test"}},"allowance":{"reason":"one_time","max_amount":9324,"currency":"usd","checkout_session_id":"<checkout id>","merchant_id":"merchant_decentra_legends_staging","expires_at":"<future ISO 8601 time within 600 seconds>"},"risk_signals":[{"type":"card_testing","score":1,"action":"authorized"}],"metadata":{"environment":"test","handler_id":"decentra_staging_card"}}
```

Complete an ACP checkout with the ACP instrument schema and credential type `spt`:

```http
POST https://decentralegends.com/acp/checkout_sessions/<checkout id>/complete
API-Version: 2026-01-30
Idempotency-Key: unique-completion-key
X-Shopping-Session-Token: <token returned by checkout creation>
Content-Type: application/json

{"payment_data":{"handler_id":"decentra_staging_card","instrument":{"type":"card","credential":{"type":"spt","token":"<delegated vt_dl_ token>"}}}}
```

## UCP A2A checkout completion

After delegated payment returns a `vt_dl_` token, complete the same cart through A2A with two data parts. Follow the [UCP A2A instrument schema](https://decentralegends.com/ucp/schemas/staging-card-a2a-instrument.json) and use credential type `PAYMENT_GATEWAY`. The ACP credential type `spt` is not valid on this route. Do not send the original `tok_visa` value. Keep the guest token and A2A `contextId` from earlier responses.

```http
POST https://decentralegends.com/a2a/message:send
A2A-Version: 1.0
Content-Type: application/a2a+json
Accept: application/a2a+json
X-A2A-Extensions: https://ucp.dev/2026-01-23/specification/reference
UCP-Agent: profile="https://agent.example/.well-known/ucp"
X-Shopping-Session-Token: <guest session token>

{"message":{"messageId":"demo-complete-001","contextId":"<A2A contextId>","role":"ROLE_USER","parts":[{"data":{"action":"complete_checkout"},"mediaType":"application/json"},{"data":{"a2a.ucp.checkout.payment":{"id":"staging-instrument","handler_id":"decentra_staging_card","type":"card","credential":{"type":"PAYMENT_GATEWAY","token":"<delegated vt_dl_ token>"}}},"mediaType":"application/json"}]}}
```

## UCP commerce

- [UCP checkout](https://decentralegends.com/ucp/checkout-sessions): Create and manage a guest checkout with a `UCP-Agent` identity URL and an `Idempotency-Key`.
- [UCP discovery standard](https://ucp.dev/): Standard protocol information for UCP clients.

## ACP specifications

- [Agentic Commerce Protocol](https://github.com/agentic-commerce-protocol/agentic-commerce-protocol): Official ACP specifications and schemas.
- [ACP payment-handler RFC](https://github.com/agentic-commerce-protocol/agentic-commerce-protocol/blob/main/rfcs/rfc.payment_handlers.md): Standard payment-handler and delegated-payment model.

## Store policies

- [Privacy](https://decentralegends.com/privacy): Demo privacy and session-data rules.
- [Terms](https://decentralegends.com/terms): Demo terms and no-purchase limits.
- [Returns](https://decentralegends.com/returns): Demo return-policy information.

## Optional

- [Human storefront](https://decentralegends.com/): Visual catalog and guest cart for human review or takeover.
- [Human pricing page](https://decentralegends.com/pricing): Visual form of the same demo pricing facts.