AgentTax
Decision Tree

Who Owes the Tax When an AI Agent Transacts?

Operator, marketplace facilitator, and merchant of record get used interchangeably to describe who is responsible for sales tax. They are not synonyms, only one of them is defined in a tax statute, and the one most often relied on in contracts is the one that decides the least. This is the four-step test, in the order it has to be run.

47
jurisdictions with facilitator statutes
4
positions in the decision tree
0
states where merchant of record decides it
DE MT NH OR
the only states with no MPF law

Merchant of record is not a tax status

Start here, because this is the assumption that sends platforms down the wrong branch. Merchant of record is a genuinely useful commercial arrangement. It is not an answer to a sales tax question, and it never appears in the decision tree below.

"We are the merchant of record, so the tax is ours."
Merchant of record is a card-network and commercial designation — the party accountable for the transaction, chargebacks, and refunds in the payment rail. It appears in no state sales tax code. No state's collection duty turns on it.
"We declined merchant-of-record status, so the tax is not ours."
More dangerous than the first. You can decline merchant-of-record status and still be a marketplace facilitator by operation of law. The statute does not ask what you agreed to.
"Our contract says the platform is responsible for all applicable taxes."
That sentence allocates cost between two private parties. It is an indemnity. It does not transfer a statutory collection obligation, and a state auditor is not a party to your contract.

The decision tree

Work it in this order, per state, per transaction type. The order matters: the first question that returns yes ends the inquiry. Running the facilitator test on a transaction that step 1 already answered is the most common expensive mistake here.

1
Are you selling your own product or service?
You are the retailer
If the agent output, compute, or API access is yours and you sell it in your own name, marketplace facilitator law is irrelevant to you. Your only question is nexus: do you have enough revenue or presence in the buyer's state to owe collection there? Stop here. Do not run the facilitator test.
role: "seller", marketplace_role: "direct"
2
Are you buying and reselling in your own name?
Retailer outbound, purchaser-for-resale inbound
If you buy compute or data and resell processed output as your own product, you are the retailer on the way out and a resale purchaser on the way in. The inbound leg needs a resale certificate. Whether an AI agent can hold and present one is genuinely unsettled — no state has addressed it — and a buyer who claims resale then consumes the input internally can leave the seller holding the liability.
role: "seller", marketplace_role: "direct" (plus a resale certificate on the inbound leg)
3
Are you facilitating someone else's sale?
Run each state's actual statutory elements
Now, and only now, the facilitator test applies — per state, per transaction type. Run the elements, not a summary chart. Do you communicate offer or acceptance? Do you collect and transmit payment? Do you list, price, brand, take orders, or provide support? Missouri needs listing AND payment. Washington needs a contract, communication, and any one of seven activities. The charts flatten exactly the variation that decides your case.
marketplace_role: "facilitator" (you collect) or "seller" (you sell through someone else's platform)
4
None of the above?
You are a vendor to the transaction, not a party to it
A pure calculation API, an observability tool, a logging layer — these sit outside the transaction. They are sold to one of the parties above; they are not themselves in the chain of sale for the goods being transacted.
not a party — your own sales are a separate role: "seller" question

Same architecture, opposite answers

47 jurisdictions have marketplace facilitator statutes and they do not share a definition. Missouri and Washington sit at opposite ends of the range. Read them side by side with one agent platform in mind.

Missouri
RSMo section 144.752(1)
Narrow — both prongs required
  • Lists or advertises the marketplace seller's property or services for sale, in any forum, AND
  • Directly or indirectly collects payment from the purchaser and transmits all or part of it to the seller
Expressly excludes persons providing only advertising or product listing without touching payment, and third-party financial institutions whose sole activity is processing payments.
For an agent platform: An orchestration platform that routes a request, transmits acceptance, and displays a price but never touches money FAILS the payment prong. Not a facilitator in Missouri.
Washington
WAC 458-20-282(104)(a)
Broad — contract + communication + any one of seven
  • Contracts with sellers to facilitate the sale of the seller's products for consideration, AND
  • Transmits or otherwise communicates the offer or acceptance between buyer and seller, AND
  • Engages in ANY ONE of: payment processing, fulfillment or storage, listing products, setting prices, branding sales as its own, taking orders, or providing customer service
A standalone payment processor performing no other marketplace function is excluded under WAC 458-20-282(201)(b)(i)(A) regardless of what it has agreed to.
For an agent platform: That same platform satisfies (i), (ii), and (iii)(D) by setting or displaying the price. It IS a facilitator in Washington. Same architecture, opposite answer, and no contract changes either result.

What is settled, and what is not

Settled: that both prongs of a narrow statute like Missouri's must be met. That contractual labels do not override statutory status. That merchant of record is not a tax designation.

Unsettled: where an agent platform that orchestrates without transacting actually lands. Our position is that facilitator obligations apply where a state's definition is unambiguously met, and that a pure tax-calculation integration sits outside facilitator classification. That is an interpretation, not a holding. No state has issued guidance on API-only platforms and no court has ruled on facilitator classification for agent orchestration.

If a state concludes your platform qualifies, you can face liability for uncollected tax alongside your merchants — both parties owing the same underlying tax. Anyone taking the narrow reading should take it knowingly.

Tell the engine which position you occupy

Once you have your answer from the tree, it is one field. marketplace_role accepts seller, facilitator, or direct. When you are a seller on a facilitating platform in a facilitator jurisdiction, the response says the marketplace is the collector of record, moves the tax out of total_tax into marketplace_remitted_tax, and sets counts_toward_nexus_threshold for that state.

REQUEST
// A seller selling THROUGH a facilitating platform, into a facilitator state.
// The facilitator is the collector of record. Whether the sale still counts
// toward your own economic-nexus threshold depends on the state; Washington counts it.
const response = await fetch("https://agenttax.io/api/v1/calculate", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-API-Key": "atx_live_..."
  },
  body: JSON.stringify({
    role: "seller",
    marketplace_role: "seller",     // seller | facilitator | direct
    amount: 2400,
    buyer_state: "WA",
    buyer_zip: "98101",
    transaction_type: "compute",
    work_type: "compute",
    counterparty_id: "buyer-agent-77"
  })
});
RESPONSE
{
  "success": true,
  "role": "seller",
  "marketplace_role": "seller",
  "amount": 2400,
  "buyer_state": "WA",
  "buyer_zip": "98101",
  "transaction_type": "compute",
  "work_type": "compute",
  "total_tax": 0,
  "marketplace_remitted_tax": 253.2,
  "collected_by_marketplace": true,
  "counts_toward_nexus_threshold": true,
  "advisories": [
    {
      "type": "marketplace_facilitator",
      "state": "WA",
      "flagged": true,
      "counts_toward_threshold": true,
      "advisory": "Marketplace facilitator law in Washington shifts collection to the facilitator, but this sale still counts toward your own economic-nexus threshold. The tax due on this transaction is reported in marketplace_remitted_tax — it is excluded from total_tax and payment routing because the facilitator collects and remits it. Registration duties can survive even when you owe no tax — see registration_relief.",
      "confidence": "high"
    }
  ]
}

What to do this week

  1. Write down which of the four positions you occupy, per state. If you cannot name it, your contracts are carrying weight they cannot hold.
  2. Stop treating your merchant-of-record clause as a tax answer. Reread it as what it is: an indemnity.
  3. Run the actual statutory elements in your five largest states rather than a vendor summary chart. The charts flatten exactly the variation that decides your case.
  4. If you are a marketplace seller on someone else's platform in a facilitator state, check, state by state, whether those sales count toward your own economic nexus threshold. Many states count them even though the platform collects; Washington is one.

Frequently asked questions

Who owes the sales tax when an AI agent buys something?
It depends on which of four positions you occupy, tested in order. If you sell your own agent output, compute, or API access in your own name, you are the retailer and your only question is nexus. If you buy and resell in your own name, you are the retailer outbound and a resale purchaser inbound. If you facilitate someone else's sale, you run each state's marketplace facilitator elements. If none of those fit, you are a vendor to the transaction, not a party to it. The order matters — the first question that returns yes ends the inquiry, and running the facilitator test on a transaction that step one already answered is the most common expensive mistake.
Does being merchant of record make us responsible for sales tax?
No. Merchant of record is a card-network and commercial designation — the party accountable for the transaction, chargebacks, and refunds in the payment rail. It is not a term of art in any state sales tax code, and no state's collection duty turns on who the card networks treat as the merchant. A contract saying the platform is responsible for all applicable taxes allocates cost between two private parties; it is an indemnity. It does not transfer a statutory collection obligation, and a state auditor is not a party to it.
Can we avoid marketplace facilitator status by declining merchant-of-record status?
No, and this is the more dangerous direction of the same error. You can decline merchant-of-record status and still be a marketplace facilitator by operation of law. Facilitator status is determined by a statute's elements — what you actually do — not by what you agreed to. Washington makes the point explicit: the duty to collect under WAC 458-20-282(301)(a) arises from the rule, not from the seller agreement, and a standalone payment processor is excluded under WAC 458-20-282(201)(b)(i)(A) regardless of its contracts.
How many states have marketplace facilitator laws?
47 jurisdictions — 46 states plus the District of Columbia. The only states without an obligation are DE, MT, NH, OR, because they have no state sales tax. Alaska is not on that list despite having no state-level sales tax: its facilitator obligation exists at the borough level through the ARSSTC, so it is treated as facilitator-capable and should be confirmed locality by locality against the buyer ZIP.
Why do Missouri and Washington reach opposite conclusions about the same platform?
Because the statutes are shaped differently. Missouri (RSMo section 144.752(1)) is narrow and requires BOTH prongs: listing or advertising the seller's property, AND directly or indirectly collecting payment from the purchaser and transmitting it to the seller. Washington (WAC 458-20-282(104)(a)) requires a contract to facilitate, transmission of offer or acceptance, and ANY ONE of seven activities — payment processing, fulfillment, listing, setting prices, branding, taking orders, or customer service. An orchestration platform that routes a request, transmits acceptance, and displays a price but never touches money fails Missouri's payment prong entirely, and satisfies Washington's third element by pricing alone. Same architecture, opposite answers, and nothing in the contract stack changes either result.
Is an agent platform that orchestrates but never touches payment a facilitator?
That is the genuinely unsettled question, and we will not pretend otherwise. What is settled: both prongs of a narrow statute must be met, and contractual labels do not override statutory status. What is not settled: where an agent platform that orchestrates without transacting lands. Our position is that facilitator obligations apply where a state's definition is unambiguously met, and that a pure tax-calculation integration sits outside facilitator classification — an interpretation, not a holding. No state has issued guidance on API-only platforms and no court has ruled on facilitator classification for agent orchestration. If a state concludes your platform qualifies, you can face liability for uncollected tax alongside your merchants, both parties owing the same underlying tax.
If I sell through a facilitating platform, do those sales count toward my economic nexus?
Not in a facilitator jurisdiction, and double-counting them is the most common quiet error we see. When the facilitator is the collector of record, the transaction should be excluded from your own economic-nexus revenue for that state. Send marketplace_role: "seller" with role: "seller" and the engine excludes the sale from your nexus tracking, sets collected_by_marketplace to true, and returns an advisory naming the state whose facilitator law shifted the obligation.
How do I tell AgentTax which position I occupy?
One field on POST /api/v1/calculate. marketplace_role accepts "seller" (you sell through someone else's facilitating platform), "facilitator" (you are the platform and the collector of record), or "direct" (the default — you are transacting on your own account). Combined with role, that resolves which party the engine treats as owing collection, whether the sale counts toward your nexus revenue, and what the audit trail records as the basis for the determination.

Related reading

The full decision-tree analysis
The long-form post this page is built from — statutory elements, exclusions, and where the genuine uncertainty sits
Economic Nexus for AI Agents
Step 1 ends at nexus. Post-Wayfair thresholds and per-agent revenue tracking
AI Agent Sales Tax
Once you know you are the retailer: rates, sourcing, and taxability across 51 jurisdictions
Agent Tax Compliance Pillar
Sales tax, nexus, machine payments, capital gains — the complete reference
51-State Classification Guide
Full state-by-state taxability matrix and sourcing rules
Machine-to-Machine Payment Tax
The compliance gap across x402, Stripe MPP, AP2, and Visa TAP
SaaS Tax Compliance for AI Agents
Knowing who owes is half of it — the other half is whether agent output is taxable software
x402 Tax Compliance Reference
Who the retailer is when settlement happens per call over x402

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