How Cartel works

Four parts, each with its own limits. No single part can both decide and pay.

Scout
AI · proposes
CAN
- Find products
- Suggest rules
- Draft plans
CAN'T
- Pay
- Change signed contracts
- Mark a rule as passed
Inspector
Engine · proves
CAN
- Check each rule against evidence
- Label who says so, and when
- Flag sources that disagree
CAN'T
- Guess
- Treat listing text as instructions
Notary
You · sign
CAN
- Sign one exact version with your passkey
- Set autonomy and maximum total
- Waive a rule that can't be checked
CAN'T
- Be skipped
- Carry a signature over to a changed contract
Guard
Checks again, then pays
CAN
- Re-check the live checkout before paying
- Pause and explain what changed
- Pay within the maximum total
CAN'T
- Pay above the maximum
- Pay if any hard rule fails

Pencil, ink, stamp

I assumedPencil: assumed or estimated. Doesn't count until you confirm.
Manufacturer saysInk: a named source states it, with a time.
SIGNED v7Stamp: committed with your passkey.

Checkout tiers

Full Cartel checkout: Re-checks, then pays within your contract.
Hand off to store: Re-checks, then the store's checkout decides.
Proof only: Proves the rules. You buy elsewhere.

What the AI does, and doesn't

The AI helps in five bounded places. It is never on the path from facts to verdict to signature to payment. If it's unavailable, Cartel still proves, signs, guards and pays.

It does

Reads your brief and drafts rules, marked “I assumed” until you confirm them
Proposes products and plans
Pulls facts out of listing text, with the exact quote it came from
Explains results in plain words, labeled “Written by AI”

It doesn't

Decide whether a rule passes: the proof engine does, the same way every time
Sign anything, or touch the payment
Follow instructions hidden in product listings

Standards used

ACP: Agentic Commerce Protocol checkout with the merchant, so the cart Cartel proves is the cart the merchant charges.
UCP: Universal Commerce Protocol, for searching the Shopify catalog.
RFC 9421 / TAP: Every request to the merchant is signed as Cartel's agent (HTTP Message Signatures, Visa Trusted Agent Protocol parameters).
WebAuthn: Your passkey signs the contract's hash, not a login challenge.
AP2: Signed contracts export as AP2-shaped mandates.

Honesty notes

GreatHub is a test merchant. Nothing ships.

Payments run in the Visa Acceptance sandbox. No real money moves.

Fit, comfort, authenticity and delivery can't be guaranteed. They show as “Can't check” or “Estimate”, never as a pass.