Do I need all 12 checks every time?

No. Core pre-sign for many agents is sanctions + drift + simulate. Add recipient or preflight when sending or paying a 402. Use Aave, Lido, vault, or passport cards when the action touches those protocols.

Is Meridian by MioDio a compliance tool?

No. Informational public-list and on-chain reads only.

Is there an MCP server?

No. Meridian by MioDio has no MCP server today. Agents call it over HTTPS with x402.

Unpaid call -> HTTP 402 -> Exact USDC on Base -> retry with PAYMENT-SIGNATURE.

How do I verify a result later?

Paid 2xx may include a signed Meridian-Receipt. Verify with /.well-known/meridian-receipt-keys.json and /receipt-verify.ts.

Docs / How agents check before signing

How AI agents check a transaction before signing (x402 pre-sign checklist)

Before an agent signs a transaction, typed data, or an x402 payment, it should verify (1) who it is paying, (2) that the unsigned payload still matches its intent, (3) what a dry run does on current chain state, and optionally (4) recipient readiness and (5) the seller's unpaid 402 terms. Meridian by MioDio exposes those as separate read-only x402 pay-per-call checks in USDC on Base (no account, no API key; never holds keys or moves funds).

The five failure modes before a signature

Wrong counterparty on a public sanctions list (exact match only).
Intent drift: the bytes no longer match what the agent meant (recipient swap, amount change, wrong selector).
Surprising execution: the dry run reverts, moves unexpected balances, or grants an unlimited approval.
Bad destination: undeployed code, freeze flags, EIP-7702 unknown wallet, lookalike poisoning.
Opaque 402 terms: paying a seller URL whose unpaid requirements or payTo you have not inspected.

A practical 3-call core (sanctions -> drift -> simulate)

GET /v1/sanctions/{address} ($0.005) for the counterparty.
POST /v1/drift ($0.005) with intent + unsigned tx or typed data.
POST /v1/simulate ($0.01) for a point-in-time dry run on Base or Ethereum.

Limits: exact-match SDN is not clearance; drift match is not a guarantee; simulate is a point-in-time dry run.

Add-ons when paying or sending (recipient, x402-preflight, payment-check)

GET /v1/recipient/{address} ($0.005) before sending.
GET /v1/x402-preflight?url= ($0.005) before signing a third-party PAYMENT-SIGNATURE.
POST /v1/payment-check ($0.005) to read any Base USDC Exact authorization or Transfer on-chain.

When Aave / Lido / vault / passport cards matter

Use these when the action touches those protocols:

Aave v3: GET /v1/risk/{address} ($0.005)
Lido stETH exit: GET /v1/lido/exit-risk?amount= ($0.005)
ERC-4626 vault: GET /v1/vault/{address} ($0.005)
Combined decision card: GET /v1/passport/{address} ($0.02) or passport + SDN ($0.02)

Passport decision.level: safe_to_interact, caution, high_risk, or unknown.

Meridian by MioDio route map

Check	Route	Price	Proves	Does not prove
OFAC SDN exact-match	GET `/v1/sanctions/{address}`	$0.005	Exact address hit on public SDN extract	Clearance; ownership; non-US lists
OFAC SDN batch (1 to 50)	POST `/v1/sanctions/batch`	$0.10	Same, up to 50 addresses	Same limits as single
Parameter drift / decoder	POST `/v1/drift`	$0.005	Intent vs decoded fields, or decode-only flags	Intent authenticity; execution outcome
Tx simulation	POST `/v1/simulate`	$0.01	Point-in-time success/revert, gas, balances	Inclusion; final outcome
Recipient readiness	GET `/v1/recipient/{address}`	$0.005	Code, freezes, EIP-7702 allowlist, OFAC, optional lookalike	That unknown is safe
x402 seller preflight	GET `/v1/x402-preflight`	$0.005	Unpaid 402 terms + payTo OFAC exact match	That you should pay
USDC payment-check	POST `/v1/payment-check`	$0.005	Nonce used, matching transfers, confirmations	Future settlement
Aave v3 risk	GET `/v1/risk/{address}`	$0.005	Pool.getUserAccountData snapshot	Advice to act
Lido exit-risk	GET `/v1/lido/exit-risk`	$0.005	Peg, queue ETA, exit liquidity for amount	Future exit path
ERC-4626 vault	GET `/v1/vault/{address}`	$0.005	Share price, lookback, idle cash	Promised share-price path
Deep passport	GET `/v1/passport/{address}`	$0.02	Joined Aave + Lido + optional vault label	Advice; invented balances
Passport + SDN	GET `/v1/passport-sanctions/{address}`	$0.02	Passport + OFAC exact match	Clearance

Payment: USDC on Base (eip155:8453), payTo 0x4DA1ED782BD61BaE9AdD5a5CaBbCf32f767f8d7F. Free demos: /v1/demo/risk, /vault, /sanctions, /drift, /simulate.

How this differs from single-purpose tools (factual, sourced)

Meridian by MioDio's case is the bundle (sanctions + drift + simulate + recipient + x402-preflight + on-chain risk reads) plus signed Meridian-Receipt headers and free demos. Cheaper sanctions-only options exist.

Public listings as checked on 2026-11-05:

Sanctions shelf density: Tanod's Bazaar snapshot (Oct 10) counted 41 priced OFAC/sanctions offers on 36 hosts, median $0.005. Source: https://tanod.dev/learn/ofac-sanctions-screening-api-prices.html
Agent402 sanctions-wallet: marketed at $0.002/call. Source: https://agent402.tools/tools/sanctions-wallet
SignCheck (youraitools): marketed $0.015 full / $0.005 lite for pre-sign tx / Permit / x402 check. Source: https://api.youraitools.co/signcheck/
x402check: preflight product positioned as check-before-paying any x402 API. Source: https://x402check.dev/
presign-guard: pre-sign verdict APIs with MCP positioning on GitHub. Source: https://github.com/Fizzl13/presign-guard. Meridian by MioDio has no MCP.
Name collision: mrdn.finance also uses "Meridian" (payment rails). This service is Meridian by MioDio.

What Meridian by MioDio does NOT do (incl. no MCP server)

Meridian by MioDio never holds keys, does not sign user transactions, and does not move funds.
Not financial, legal, or compliance advice.
Not a substitute for a compliance program.
No MCP server and no SDK are available today.
Does not claim to be the cheapest sanctions screen.

Try free demos

curl -s "https://meridian.miodiollc.com/v1/demo/sanctions"
curl -s "https://meridian.miodiollc.com/v1/demo/drift"
curl -s "https://meridian.miodiollc.com/v1/demo/simulate"
curl -s "https://meridian.miodiollc.com/v1/demo/risk"
curl -s "https://meridian.miodiollc.com/v1/demo/vault"

Unpaid calls return HTTP 402 with PAYMENT-REQUIRED. Retry with PAYMENT-SIGNATURE.

FAQ

Do I need all 12 checks every time?: No. Core pre-sign for many agents is sanctions + drift + simulate. Add recipient or preflight when sending or paying a 402. Use Aave, Lido, vault, or passport cards when the action touches those protocols.
Is Meridian by MioDio a compliance tool?: No. Informational public-list and on-chain reads only.
Is there an MCP server?: No. Meridian by MioDio has no MCP server today. Agents call it over HTTPS with x402.
How do I pay?: Unpaid call -> HTTP 402 -> Exact USDC on Base -> retry with PAYMENT-SIGNATURE.
How do I verify a result later?: Paid 2xx may include a signed Meridian-Receipt. Verify with /.well-known/meridian-receipt-keys.json and /receipt-verify.ts.