Facet UCP Shopping
The independent agent-commerce protocol for AI-agent checkout on any online store.
Should I use this
Quality & Safety
Findings (6)
- HIGH
- MEDIUMin discover_businesses
- MEDIUMin discover_products
- MEDIUMin get_quote
- MEDIUMin post_delivery_refund
- LOWin lookup_catalog
Based on automated analysis of tool definitions and protocol compliance.
Context Cost
This is the approximate number of tokens consumed each time the server's tools are loaded into a model's context. Higher counts reduce the attention available for other tasks.
Install
One-Click Install
Add this to your `claude_desktop_config.json` file:
{
"mcpServers": {
"ucp-shopping": {
"url": "https://api.facet.llc/ucp/mcp"
}
}
}Remote endpoints
https://api.facet.llc/ucp/mcpstreamable-httpWhat it can do
Tool inventory
Tools (23)
🟢search_catalog(catalog)
Search the merchant catalog for products matching a free-text query.
Input Schema
{
"type": "object",
"properties": {
"catalog": {
"type": "object",
"properties": {
"query": {
"type": "string",
"description": "Free-text search query."
},
"pagination": {
"type": "object",
"properties": {
"cursor": {
"type": "string"
},
"limit": {
"type": "integer",
"minimum": 1
}
}
}
}
}
},
"required": [
"catalog"
]
}⚪lookup_catalog(catalog)
Look up one or more products or variants by identifier (batch).
Input Schema
{
"type": "object",
"properties": {
"catalog": {
"type": "object",
"required": [
"ids"
],
"properties": {
"ids": {
"type": "array",
"items": {
"type": "string"
},
"minItems": 1,
"maxItems": 100
}
}
}
},
"required": [
"catalog"
]
}🟢get_product(catalog)
Get full product detail by product or variant identifier.
Input Schema
{
"type": "object",
"properties": {
"catalog": {
"type": "object",
"required": [
"id"
],
"properties": {
"id": {
"type": "string"
}
}
}
},
"required": [
"catalog"
]
}🟡discover_businesses(query, near, radius_km, limit)
Find businesses in the Facet Universal Business Index that an agent can transact with. Returns `featured` (claimed merchants with a live `terminal_url` — point your catalog and checkout calls there) and `results` (the wider directory). Use this first when you do not already know which merchant to talk to. REQUIRES IDENTITY: send a Facet KYA as `Authorization: Bearer <kya>` on the MCP request. A KYA is an ES256 JWT from Facet's default issuer https://issuer.facet.llc (or another issuer this Terminal trusts — see KYA-Issuers in its /.well-known/agents.txt). Calling without one returns 401 with a signup link.
Input Schema
{
"type": "object",
"properties": {
"query": {
"type": "string",
"description": "Free-text query, e.g. \"flowers\" or \"makeup brushes\"."
},
"near": {
"type": "object",
"description": "Optional geographic center to rank by proximity.",
"properties": {
"lat": {
"type": "number",
"description": "Latitude, decimal degrees."
},
"lng": {
"type": "number",
"description": "Longitude, decimal degrees."
}
},
"required": [
"lat",
"lng"
]
},
"radius_km": {
"type": "number",
"description": "Search radius around `near`, km. Default 25."
},
"limit": {
"type": "integer",
"minimum": 1,
"maximum": 50,
"description": "Max matches to return. Default 10, cap 50."
}
}
}🟡discover_products(query, category, tags, limit)
Search products ACROSS every merchant in the Facet network that has opted into cross-merchant discovery. Returns matches each carrying the selling merchant's `terminal_url` (point your catalog and checkout calls there). Filter by free-text `query` (product name + description), exact `category`, and/or `tags` (all must be present); at least one filter is required. Use this when you know WHAT you want but not WHICH merchant sells it. REQUIRES IDENTITY: send a Facet KYA as `Authorization: Bearer <kya>` on the MCP request. A KYA is an ES256 JWT from Facet's default issuer https://issuer.facet.llc (or another issuer this Terminal trusts; see KYA-Issuers in its /.well-known/agents.txt). Calling without one returns 401 with a signup link.
Input Schema
{
"type": "object",
"properties": {
"query": {
"type": "string",
"description": "Free-text over product name + description, e.g. \"lavender soap\"."
},
"category": {
"type": "string",
"description": "Exact product category to match."
},
"tags": {
"type": "array",
"items": {
"type": "string"
},
"description": "Tags that must ALL be present on a matching product."
},
"limit": {
"type": "integer",
"minimum": 1,
"maximum": 50,
"description": "Max matches to return. Default 10, cap 50."
}
}
}🟡get_quote(product_id, qty, site_id, fulfillment)
Get the real landed cost of a product from this merchant: goods + shipping + tax for a specific destination, plus a signed `quote_token` the payment path binds to. Call this before paying — the token is what makes the price the MERCHANT's, not one you name. Physical products REQUIRE a `fulfillment` ship-to; without one you get FULFILLMENT_REQUIRED. An unserviceable destination returns UNDELIVERABLE (the merchant's own shipping zones, which Facet cannot waive). REQUIRES IDENTITY: send a Facet KYA as `Authorization: Bearer <kya>` (ES256 JWT from https://issuer.facet.llc, or another issuer in this Terminal's agents.txt KYA-Issuers).
Input Schema
{
"type": "object",
"properties": {
"product_id": {
"type": "string",
"description": "Product or variant id, e.g. from search_catalog."
},
"qty": {
"type": "integer",
"minimum": 1,
"description": "Quantity. Default 1."
},
"site_id": {
"type": "string",
"description": "Usually omitted — this Terminal's bound site is used."
},
"fulfillment": {
"type": "object",
"description": "Ship-to destination. REQUIRED for physical products.",
"properties": {
"mode": {
"type": "string",
"enum": [
"inline",
"ref"
],
"description": "`inline` with a full address, or `ref` to reuse a prior fulfillment_ref."
},
"fulfillment_ref": {
"type": "string",
"description": "Opaque ref from a prior quote (mode `ref`)."
},
"address": {
"type": "object",
"description": "All six fields are required, including `region`.",
"required": [
"recipient",
"line1",
"locality",
"region",
"postal_code",
"country"
],
"properties": {
"recipient": {
"type": "string"
},
"line1": {
"type": "string"
},
"line2": {
"type": "string"
},
"locality": {
"type": "string",
"description": "City."
},
"region": {
"type": "string",
"description": "State/province. Required even where the country has none."
},
"postal_code": {
"type": "string"
},
"country": {
"type": "string",
"description": "ISO 3166-1 alpha-2, e.g. US."
},
"phone": {
"type": "string"
}
}
}
}
}
},
"required": [
"product_id"
]
}🟢get_payment_capabilities
Which settlement rails this merchant actually accepts (e.g. coin/boson-escrow for escrowed funds that release on fulfilment, coin/usdc-base for direct). Call before get_payment_requirements so you pass a rail_id this merchant registers, rather than guessing. No identity required — this is discovery data.
Input Schema
{
"type": "object",
"properties": {}
}🟢get_payment_requirements(product_id, qty, rail_id, amount, quote_token, ...)
Turn a `quote_token` from get_quote into a seller-signed payment offer to authorize. Returns `requirements` (escrow address, asset, exact atomic amount, network) — sign it LOCALLY with your own wallet (e.g. @bosonprotocol/x402-client handle402 for `coin/boson-escrow`, producing an X-PAYMENT string). Facet never holds your key and cannot sign for you, which is why paying is two steps and not one. The offer binds to the quote_token's sealed landed total and ship-to, so the amount is the merchant's, not one you name. REQUIRES IDENTITY: same Facet KYA as get_quote, and the SAME `aid` — the offer path rejects a quote_token issued to a different agent than the caller.
Input Schema
{
"type": "object",
"properties": {
"product_id": {
"type": "string",
"description": "Must match the product the quote_token sealed."
},
"qty": {
"type": "integer",
"minimum": 1,
"description": "Must match the quote_token. Default 1."
},
"rail_id": {
"type": "string",
"description": "Settlement rail, e.g. \"coin/boson-escrow\" (escrow: funds release on fulfilment) or \"coin/usdc-base\". See /v1/payments/capabilities for what this merchant registers."
},
"amount": {
"type": "object",
"required": [
"amount",
"currency"
],
"description": "The landed total in ATOMIC units. Must equal the quote_token's sealed total.",
"properties": {
"amount": {
"type": "integer",
"description": "Atomic units, e.g. 16930000 for $16.93 USDC (6dp)."
},
"currency": {
"type": "string",
"description": "e.g. \"USDC\"."
}
}
},
"quote_token": {
"type": "string",
"description": "The signed token from get_quote."
},
"site_id": {
"type": "string",
"description": "Usually omitted — this Terminal's bound site is used."
}
},
"required": [
"product_id",
"rail_id",
"amount",
"quote_token"
]
}🟢get_order(order_id)
Read back one of YOUR orders on this merchant: status, amount, settlement state. Use the order_id returned when you paid. You can only read orders your own agent identity placed — another agent's order returns FORBIDDEN. REQUIRES IDENTITY: Facet KYA as `Authorization: Bearer <kya>`.
Input Schema
{
"type": "object",
"properties": {
"order_id": {
"type": "string",
"description": "The order id returned at payment."
}
},
"required": [
"order_id"
]
}🟢list_orders(limit, cursor)
List YOUR order history on this merchant, newest first. Scoped to your own agent identity — you never see another agent's orders. REQUIRES IDENTITY: Facet KYA as `Authorization: Bearer <kya>`.
Input Schema
{
"type": "object",
"properties": {
"limit": {
"type": "integer",
"minimum": 1,
"description": "Max orders to return."
},
"cursor": {
"type": "string",
"description": "Opaque cursor from a previous page."
}
}
}🟡post_delivery_refund(order_id, reason, refund_line_items, receipt)
Request a refund or return on a DELIVERED order you placed on this merchant. Opens a merchant-approved refund ticket (status `requested`); it moves NO money on its own. The merchant reviews and approves it, and only then does the send-back sign from the merchant's OWN wallet (non-custodial). Amount and recipient are NOT inputs: the refund amount is derived and capped server-side, and the recipient is the order's stamped payer, never one you name. Pass `refund_line_items` to refund only part of the order; omit for the whole order. Owner-scoped: another agent's order returns FORBIDDEN. REQUIRES IDENTITY: a Facet KYA as `Authorization: Bearer <kya>` (an ES256 JWT from https://issuer.facet.llc, or another issuer in this Terminal's agents.txt KYA-Issuers). A wallet-bound KYA also authorizes a platform-originated order by its stamped payer.
Input Schema
{
"type": "object",
"properties": {
"order_id": {
"type": "string",
"description": "The order id returned at payment (settle / checkout complete). A reservation id is not an order id."
},
"reason": {
"type": "string",
"description": "Why the refund or return is requested. Required."
},
"refund_line_items": {
"type": "array",
"description": "Optional PARTIAL selection: refund only these lines instead of the whole order. Advisory at request time; the merchant is authoritative and may adjust it at decide. Omit for a full-order refund.",
"items": {
"type": "object",
"required": [
"product_id",
"qty"
],
"properties": {
"product_id": {
"type": "string",
"description": "A product id present in the order."
},
"qty": {
"type": "integer",
"minimum": 1,
"description": "At most the ordered quantity for that line."
}
}
}
},
"receipt": {
"type": "object",
"description": "Optional Ed25519-signed settlement receipt (the signed settle response you received). When valid and bound to this order it records receipt_verified on the ticket; it never gates the refund.",
"properties": {
"body": {
"type": "string"
},
"signature": {
"type": "string"
},
"trace_id": {
"type": "string"
},
"path": {
"type": "string"
}
}
}
},
"required": [
"order_id",
"reason"
]
}🟡wishlist_add(product_id, note)
Save a product to YOUR wishlist on this merchant for later. Idempotent: saving the same product again updates its note and keeps the original save time. Scoped to your own agent identity. REQUIRES IDENTITY: Facet KYA as `Authorization: Bearer <kya>`.
Input Schema
{
"type": "object",
"properties": {
"product_id": {
"type": "string",
"description": "The product id to save."
},
"note": {
"type": "string",
"description": "Optional short note. No personal data."
}
},
"required": [
"product_id"
]
}🟢wishlist_list(limit)
List YOUR saved items (wishlist) on this merchant, newest first. Scoped to your own agent identity, so you never see another agent's list. REQUIRES IDENTITY: Facet KYA as `Authorization: Bearer <kya>`.
Input Schema
{
"type": "object",
"properties": {
"limit": {
"type": "integer",
"minimum": 1,
"description": "Max items to return."
}
}
}🔴wishlist_remove(product_id)
Remove a product from YOUR wishlist on this merchant. Idempotent: removing something not on your list succeeds with removed:false. Scoped to your own agent identity. REQUIRES IDENTITY: Facet KYA as `Authorization: Bearer <kya>`.
Input Schema
{
"type": "object",
"properties": {
"product_id": {
"type": "string",
"description": "The product id to remove."
}
},
"required": [
"product_id"
]
}🟡create_checkout(line_items, cart_id, fulfillment)
Open a checkout session for one or more catalog line items (or promote a cart with `cart_id`). Returns the session plus server-resolved `payment_handlers` (rail, pay_to, exact amount) to satisfy: the price and pay_to are the MERCHANT's, sealed here, never read from your request. Physical goods REQUIRE a `fulfillment` ship-to (else FULFILLMENT_REQUIRED), sealed at create. REQUIRES IDENTITY on a signature-required Terminal: a Facet KYA as `Authorization: Bearer <kya>`.
Input Schema
{
"type": "object",
"properties": {
"line_items": {
"type": "array",
"description": "Items to buy, each `{ item: { id }, quantity }`. Omit when using cart_id.",
"items": {
"type": "object",
"properties": {
"item": {
"type": "object",
"properties": {
"id": {
"type": "string"
}
},
"required": [
"id"
]
},
"quantity": {
"type": "integer",
"minimum": 1
}
}
}
},
"cart_id": {
"type": "string",
"description": "Promote an existing cart: its stored lines drive the checkout and any line_items are ignored (the business must use the cart contents)."
},
"fulfillment": {
"type": "object",
"description": "Ship-to destination. REQUIRED for physical products; sealed at create."
}
}
}⚪complete_checkout(checkout_id, payment)
Complete a checkout you created and place the order by submitting the buyer-signed payment credential. This is the MONEY-MOVING leg: funds capture on-chain to the merchant's pay_to (x402) or into escrow (Boson). The amount is re-derived server-side from the reservation, never your request, and the buyer's signature is verified before any capture. A per-buyer refusal (FORBIDDEN, cap-exceeded, FULFILLMENT_REQUIRED) returns as an error result; a missing or invalid identity is a real 401. REQUIRES IDENTITY plus a signed Idempotency-Key on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"checkout_id": {
"type": "string",
"description": "The checkout id from create_checkout."
},
"payment": {
"type": "object",
"description": "The payment container `{ instruments: [{ credential: { type, ... } }] }`, where credential.type is `x402_authorization` or `boson_commit_authorization`. Sign the seller-signed offer LOCALLY with your own wallet; Facet never holds your key."
}
},
"required": [
"checkout_id",
"payment"
]
}🟢get_checkout(id)
Read back one of YOUR checkout sessions by id: status, totals, line items, payment_handlers. Owner-scoped, so another agent's id returns not_found. REQUIRES IDENTITY on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The checkout session id."
}
},
"required": [
"id"
]
}🟡update_checkout(id)
Return a checkout's CURRENT sealed snapshot. Facet seals price and items at create, so this is a no-op that reports the session plus a note: to change line items, update the cart and start a new checkout with create_checkout(cart_id). Owner-scoped.
Input Schema
{
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The checkout session id."
}
},
"required": [
"id"
]
}🔴cancel_checkout(id)
Cancel a checkout session before completion, releasing its inventory hold. Idempotent, owner-scoped, and moves no money (distinct from an escrow refund). REQUIRES IDENTITY plus an Idempotency-Key on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The checkout session id."
}
},
"required": [
"id"
]
}🟡create_cart(line_items)
Create a pre-checkout cart from catalog line items. A cart is a mutable scratchpad: it moves no money and holds no inventory, so it carries estimated (server-derived) totals and NO payment_handlers. Assemble it, then create_checkout(cart_id) to convert. REQUIRES IDENTITY on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"line_items": {
"type": "array",
"description": "Items, each `{ item: { id }, quantity }`. Prices are catalog-derived, never yours.",
"items": {
"type": "object",
"properties": {
"item": {
"type": "object",
"properties": {
"id": {
"type": "string"
}
},
"required": [
"id"
]
},
"quantity": {
"type": "integer",
"minimum": 1
}
}
}
}
}
}🟢get_cart(id)
Read back one of YOUR carts by id: line items and estimated totals. Owner-scoped, so another agent's id returns not_found. REQUIRES IDENTITY on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The cart id."
}
},
"required": [
"id"
]
}🟡update_cart(id, line_items)
Replace a cart's line items (full replacement), re-priced server-side. Owner-scoped. REQUIRES IDENTITY on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The cart id."
},
"line_items": {
"type": "array",
"description": "The new full set of items, each `{ item: { id }, quantity }`.",
"items": {
"type": "object",
"properties": {
"item": {
"type": "object",
"properties": {
"id": {
"type": "string"
}
},
"required": [
"id"
]
},
"quantity": {
"type": "integer",
"minimum": 1
}
}
}
}
},
"required": [
"id"
]
}🔴cancel_cart(id)
Cancel a cart. Idempotent, owner-scoped, and moves no money. REQUIRES IDENTITY plus an Idempotency-Key on a signature-required Terminal.
Input Schema
{
"type": "object",
"properties": {
"id": {
"type": "string",
"description": "The cart id."
}
},
"required": [
"id"
]
}Recommended Prompts
search_catalogsearch_catalogget_productget_productlist_ordersCommunity
Evidence