# Sapient MPP Reference Sandbox - Agent Payment Report

- Domain: usesapient.com
- Category: Reference Fixtures
- Company type: machine_api
- Protocols: mpp
- Agent integration surfaces: None cataloged
- Payer platforms or methods: Sapient fixture wallet
- Vendor roles: None cataloged
- Verification level: **sandbox_verified**
- Score version: `agent-payments-v4`
- Reference fixture: Yes
- Last verified: 2026-08-10T20:01:35+00:00

## Protocol documentation

- MPP: No protocol-specific documentation attached.

## Scores

| Dimension | Score |
|-----------|-------|
| Payment readiness | 84 |
| Website experience | — |
| Agent experience | 100 |
| Overall score | 89 |
| Grade | A |

An em dash means the company has not reached the evidence level required for that score. A public protocol claim is not treated as a completed payment.

## Protocol Readiness Suites

Each suite separates applicability, public claims, discovery, protocol validation, safety, live execution, delivery, receipts, and recovery. Missing evidence is reported as not evaluated rather than inferred as support or failure.

### x402 V2 agent payment acceptance

- Cataloged for this company: No
No completed x402 V2 agent payment acceptance suite is attached. Applicability and conformance remain not evaluated.

### MPP machine payment acceptance

- Cataloged for this company: Yes
No completed MPP machine payment acceptance suite is attached. Applicability and conformance remain not evaluated.

### UCP agentic checkout readiness

- Cataloged for this company: No
No completed UCP agentic checkout readiness suite is attached. Applicability and conformance remain not evaluated.

### ACP merchant checkout readiness

- Cataloged for this company: No
No completed ACP merchant checkout readiness suite is attached. Applicability and conformance remain not evaluated.

### AP2 delegated authorization readiness

- Cataloged for this company: No
No completed AP2 delegated authorization readiness suite is attached. Applicability and conformance remain not evaluated.

### Visa TAP trusted-agent readiness

- Cataloged for this company: No
No completed Visa TAP trusted-agent readiness suite is attached. Applicability and conformance remain not evaluated.

### Mastercard Agent Pay acceptance evidence

- Cataloged for this company: No
No completed Mastercard Agent Pay acceptance evidence suite is attached. Applicability and conformance remain not evaluated.

### Agent payment website experience

No complete agent-payment website scan is attached.

## Frequently Asked Questions

### Who should set up x402?

Pick x402 when the thing being sold is a single HTTP-accessible resource: an API response, dataset export, generated report, inference call, paywalled file, crawl result, or metered compute job. The clean implementation is request-scoped: the agent asks for a URL, receives a 402 challenge with payment terms, pays, then retries or continues the same request.

Fits: API companies, data providers, AI inference providers, developer infrastructure, paywalled content, search or scraping providers, analytics APIs, and MCP tools whose paid action maps to a URL. It is usually not the first protocol for carts, shipping, variants, returns, or marketplace checkout.

### Who should set up MPP?

Pick MPP when you need a machine-payment flow that is broader than one fixed paid URL: a challenge, credential, and receipt flow that can support multiple payment methods, one-time charges, measured sessions, subscriptions, HTTP services, and MCP tools. It is strongest when payer choice, receipts, and recurring or usage-based access matter.

Fits: SaaS platforms with public APIs, cloud services, metered data products, AI tools, API marketplaces, and paid MCP tools that may accept cards, stablecoins, Stripe-backed payments, or custom payment methods. It is less useful when the main job is retail product discovery and checkout.

### Where does MCP fit?

Use MCP when the agent should operate the product through named tools instead of raw endpoints: create a ticket, run a query, generate a file, start a workflow, reserve inventory, or read private account data. MCP describes the tool interface and context; x402, MPP, or another payment mechanism still needs to describe how the charge is authorized.

Fits: developer tools, authenticated SaaS products, observability platforms, CRMs, workflow software, data tools, design or document tools, and internal enterprise platforms. MCP alone should not be counted as payment support; it needs a reproducible paid action behind it.

### Who should set up UCP?

Pick UCP when the goal is direct buying from AI surfaces such as Google AI Mode or Gemini while the merchant stays the merchant of record. It is about exposing commerce capabilities, checkout options, payment handlers, and post-purchase state so an agent can move from discovery to purchase without sending the user through a normal browser flow.

Fits: retailers with Merchant Center feeds, DTC brands, commerce platforms, marketplaces, and merchants in expanding direct-buying categories such as lodging and food. It is overkill for a simple paid API endpoint with no catalog, checkout, or order lifecycle.

### Who should set up ACP?

Pick ACP when the main integration is agentic checkout: product feed or cart discovery, checkout-session create/update/complete, fulfillment choices, delegated payment, delegated authentication, and order or refund webhooks. It is a checkout contract for agents, not a generic API monetization layer.

Fits: Stripe-based merchants, ecommerce platforms, marketplaces, product-feed owners, checkout providers, DTC brands, and merchants pursuing ChatGPT or agent-shopping checkout. It is not the first step for API-only companies unless they also sell products or checkout sessions.

### Who should set up AP2?

Pick AP2 when the hard part is proving agent authority. The user gives a real-time approval or a delegated mandate, the agent shops or coordinates within those constraints, and the merchant or payment provider needs cryptographic evidence that the final payment matched the approved intent.

Fits: travel booking, procurement, marketplace checkout, ticketing, delivery, financial services, high-value retail, and B2B agent workflows where the user may not be present at final purchase time. It is less relevant for fixed-price API calls where the payer approves each request directly.

### Who should set up Visa TAP?

Pick Visa Trusted Agent Protocol when the immediate problem is merchant visibility and trusted-agent recognition: distinguishing legitimate shopping agents from generic bots, verifying signed agent requests, and deciding what consumer, intent, and payment information an agent can pass during commerce.

Fits: large merchants, bot-mitigation or CDN partners, PSPs, wallets, agent platforms, and commerce teams integrating with Visa Intelligent Commerce. Generic Visa card acceptance is not enough; the implementation needs TAP-style agent identity and signature handling.

### Who should set up Mastercard Agent Pay?

Pick Mastercard Agent Pay when Mastercard network tokenization is part of the agentic checkout path. The implementation is about agentic tokens, Mastercard Digital Enablement Service, authentication such as payment passkeys, role registration, and transaction identifiers that let the network, issuer, acquirer, merchant, and agentic-commerce provider understand the transaction.

Fits: agentic commerce providers, agentic commerce enablers, token requestors, large merchants, issuers, acquirers, wallets, and checkout providers participating in Mastercard's Agent Pay program. A normal Mastercard card form or generic card-on-file checkout does not qualify.

## Coding-Agent Evaluations

| Agent | Status | Score |
|-------|--------|-------|
| Claude Code | passed | 100 |
| Codex | passed | 100 |

## Services and Endpoints

- No endpoint inventory attached.

## External Website Benchmarks

- No external website benchmark attached.

External scores provide website context and do not contribute to Lightsage's payment-readiness score.

## Evidence

- [Claude Code and Codex bounded MPP sandbox run (2026-08-10)](https://usesapient.com/data/agent-payments-reference-runs.json)

Canonical URL: https://lightsage.com/agent-experience-arena/payments/sapient-mpp-reference