Paygent isn't a proprietary API — it's an agent that speaks the Universal Commerce Protocol: a discovery document, an agent card, and an MCP checkout endpoint. If your runtime can call a tool, it can sell, watch prices, optimize cards, and complete checkout.
All money and points math is deterministic and server-side — never delegated to a model.
# 1 · Discover the agent over standard surfaces card = fetch("https://shopchat.agent/.well-known/agent_card.json") ucp = fetch("https://shopchat.agent/.well-known/ucp") # 2 · Open a session bound to YOUR wallet provider session = paygent.session( user="usr_8f3a", wallet_provider="your-bank-or-program", # pluggable ) # 3 · Arm an autonomous purchase, bounded by a mandate session.watch( product="wh-1000xm6", target="-15%", mandate={ "max_amount": 400.00, "scope": "this_cart", "expires": "7d" }, ) # → price hits · best card computed · points applied # → checkout completes with a verifiable authorization
/.well-known/ucp
Agent card · /.well-known/agent_card.json
MCP checkout · /ucp/mcp
UCP Loyalty Extension · end-to-end
No proprietary SDK required to start — the same surfaces the UCP ecosystem uses for discovery and checkout are how you talk to Paygent.
A published, verifiable identity for the commerce agent — what it can do, how to reach it, and the key material to authenticate it. Your host runtime discovers capability the standard way.
The /.well-known/ucp document declares checkout schemas, payment handlers, and the loyalty extension — machine-readable, versioned, and standard across the ecosystem.
Create, update, complete, and cancel checkouts as MCP tool calls — idempotency keys preserved end-to-end, loyalty block on every response.
Anyone can wire an LLM to a product feed. What you don't want to build twice:
Totals, discounts, and point earning are computed by audited services and forced verbatim into agent output. The model decides what; it never invents how much.
Autonomous purchases carry a user-scoped, expiring, merchant-verifiable authorization — amount-bounded and cart-bounded. Cryptographic accountability, not a chat log.
Bind sessions to your wallet provider — cards, balances, points. The loyalty engine handles escrow, real-time redemption, and crash-safe capture behind one interface.
Price watches complete checkouts while the user is away — idempotent, replay-protected, and bounded by the mandate they approved.
Local or hosted models, swapped by configuration. The correctness lives in the services, so the agent works on a 8B model or a frontier one.
Every checkout response carries the UCP Loyalty Extension: earning forecast, per-rule breakdown, applied discounts — ready for your UI to render.
Your existing assistant delegates commerce intents to Paygent over MCP / agent-card discovery. Lightest touch.
Drop the chat surface into your iOS or web app with reference SDKs — sessions, checkout widgets, wallet sync.
Run the full engine under your brand with your catalog and your wallet provider behind the interface.
Whichever path: arm price watches with mandates and let checkouts complete on your users' terms.
We're onboarding a small number of design partners — host runtimes, platforms, and wallet providers — ahead of general availability.