Agentic Rails Atlasby merces.ai

Persona

Payment facilitator or relay operator

Verifies and settles, pays gas, screens sanctions.

Verified (verified under 30 days ago)

Role

Goals

  • Verify signed payment payloads fast enough that a 402 retry adds milliseconds, not seconds.
  • Settle on chain reliably, pay the gas, and return a transaction hash the server can log.
  • Support many schemes and networks (exact, upto, batch-settlement, auth-capture across CAIP-2 networks) behind one /verify and /settle API.
  • Screen payers and payees against sanctions lists without blocking honest traffic.
  • Earn a predictable fee per settlement or per unit of volume.
  • Publish accurate /supported data and revenue feedback so agents and indexers can rely on it.

Pains

  • Research found every tested facilitator broke at least one safety rule, and fixing those rules while keeping latency low is hard.
  • Clients replay nonces and present expired validBefore windows, and each bad payload still costs a verify.
  • Gas price spikes make small settlements unprofitable, and batching changes the trust model.
  • The facilitator is a central party in a protocol that is supposed to be open, so centralization criticism lands here.
  • Sanctions and AML obligations are unclear for a party that never holds funds but does move them.
  • Leaderboard farming and manufactured volume route through facilitators and distort their metrics.

Decisions they own

  • Which schemes, networks and assets to support, and the maximum amount per settlement.
  • Fee model: free tier, per-transaction, or basis points.
  • Sanctions screening provider and what to do on a hit.
  • Whether to offer payment flows beyond authorization (upfront, escrow) and refund paths.
  • What to publish about settled volume and how to filter farmed activity.

Vocabulary

  • verify
  • settle
  • /supported
  • gas
  • nonce
  • validBefore
  • EIP-3009
  • transferWithAuthorization
  • Permit2
  • CAIP-2
  • batch-settlement
  • auth-capture
  • sanctions screening
  • fee payer

Each protocol from this seat

Relevance levels: High, a main persona on the protocol page; Medium, owns, implements or verifies a step; Low, relies on or observes a step; None, no role found in the protocol page.

ERC-8004: Trustless Agents

Relevance: None

Not one of the main personas on the ERC-8004: Trustless Agents page. The responsibility table gives this persona no step.

x402

Relevance: High

Operates the verify and settle service, pays gas, and publishes what it supports. Source [1, 2, 3, 4, 5]

Goals

  • Verify fast and settle reliably across networks
  • Recover gas and costs through fees
  • Avoid settling anything twice

Pains

  • Duplicate settlement races and Solana duplicate submissions
  • Keeping signer keys funded for gas
  • Sanctions screening and its legal exposure

Implements

  • POST /verify, POST /settle and GET /supported
  • Nonce and replay checks, simulation and settlement caches
  • KYT and OFAC screening where it chooses to offer it

Must trust

  • RPC providers and chain finality
  • The token contracts (EIP-3009, Permit2 proxies)
  • Resource servers to send their own requirements, not the client's echo

Questions they ask

  • Which schemes and networks do I list in /supported?
  • How do I make /settle idempotent across processes?
  • What do I return when a receipt never arrives?

First three steps

  1. Run a self-facilitation example against a testnet
  2. Implement the eight facilitator safety rules from the security literature
  3. Publish /supported with signers per CAIP-2 family

Metrics they care about

  • Verify and settle success rates
  • Gas cost per settlement
  • settlement_pending share
  • Screening hits

A day in the life. Priya runs a facilitator for three EVM chains and Solana. Her /supported answer lists exact and upto on each chain and one signer per family. Most of her day is not cryptography but operations: keeping the gas wallets topped up, watching the share of settles that end as settlement_pending, and making sure a retried settle from a second worker cannot broadcast twice. A paper on facilitator safety rules lands, and she maps each rule to a test. Screening runs before every settle; when a payer address matches a sanctions list, the settle fails with a clear reason and the resource server returns 402 instead of the data.

Steps in the responsibility table

  • OwnsVerify the payload (POST /verify)
  • ImplementsScreen for sanctions (KYT, OFAC)
  • OwnsSettle on chain and pay gas (POST /settle)
  • ImplementsReconcile settlement_pending
  • ObservesMonitor spend and anomalies

Visa Trusted Agent Protocol

Relevance: None

Not one of the main personas on the Visa Trusted Agent Protocol page. The responsibility table gives this persona no step.

Agentic Commerce Protocol (ACP)

Relevance: None

Not one of the main personas on the Agentic Commerce Protocol (ACP) page. The responsibility table gives this persona no step.

UCP

Relevance: None

Not one of the main personas on the UCP page. The responsibility table gives this persona no step.

AP2

Relevance: None

Not one of the main personas on the AP2 page. The responsibility table gives this persona no step.

Mastercard Agent Pay

Relevance: None

Not one of the main personas on the Mastercard Agent Pay page. The responsibility table gives this persona no step.

Sources

  1. x402 Protocol Specification v2 (external link)x402 Foundation. Specification, primary source. Published . Accessed .
  2. x402 docs: Facilitator (external link)x402 Foundation. Documentation, primary source. Accessed .
  3. When HTTP 402 Meets the Blockchain: Risks on Emerging x402 Payments (external link)arXiv. Paper, primary source. Published . Accessed .
  4. CDP x402 facilitator docs (pricing, networks, KYT and OFAC) (external link)Coinbase Developer Platform. Documentation, primary source. Accessed .
  5. GHSA-qr2g-p6q7-w82m: facilitators processing Solana payments (external link)GitHub Advisory Database. Other, primary source. Published . Accessed .

Source details

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