Skip to main content
Schema B is the writer attestation — a registered lender’s signed verdict on a merchant. Every approved lending application that mints on-chain mints a Schema B row, anchoring the line ceiling, term, rate, and methodology hash for downstream consumers (order credit-leg, attribution credit-leg, lender-agent quote enrichment).
Schema nameCreditRiskAttestation
EAS revocableyes
Expiry semanticsrequired (expiresAt is mandatory; lender re-underwrites at expiry)
Issued byA wallet currently ACTIVE in LenderRegistry
SubjectMerchant (subjectRootUid)
MCP toolverify_credit_risk
Verifier APIGET /v2/attestations/credit-risk/:merchantId
Composite readGET /v2/underwriting-signals/:merchantId

​
Network & UIDs

NetworkEAS contractSchema UIDExplorer
Base mainnet0x42000000000000000000000000000000000000210xbd652f94a034edea8635b1f87d05f2b33b23c0243430c2dae91469103921c7bdbasescan · easscan schema
Base Sepolia0x4200000000000000000000000000000000000021resolve via chain field on /v2/attestations/credit-risk/:merchantIdsepolia.basescan
EAS registry version: v1.4.0.

​
Field reference

ABI schema string: 
string subjectRootUid, uint8 creditTier, uint64 maxCreditLineUsdCents,
uint32 termDays, uint32 rateBps, bytes32 methodologyHash, uint256 expiresAt
FieldSolidity typeSemanticMutability
subjectRootUidstringSubject anchor. Production form: "merchant:<merchantId>". Post-rotation: keccak256(entityType||entityId) bytes32 (legacy + new coexist during transition).immutable per attestation
creditTieruint8Resolved credit tier at issuance. Encoded T0=0 / T1=1 / T2=2 / T3=3. Snapshot from CreditTierMappingService at mint time.immutable per attestation
maxCreditLineUsdCentsuint64Maximum credit line in USD cents (getLineCeilingUsd × 100).immutable per attestation
termDaysuint32Quoted repayment term in days. DTO layer enforces 1-1800 (5y) before mint.immutable per attestation
rateBpsuint32Quoted APR in basis points (850 = 8.50%).immutable per attestation
methodologyHashbytes32keccak256 of the lender’s published underwriting methodology document. Cross-references the methodology registry.immutable per attestation
expiresAtuint256Unix seconds. Required; a re-underwrite mints a new attestation.immutable per attestation
EAS envelope fields:
Envelope fieldTypeSemantic
uidbytes32Attestation UID.
schemabytes32Schema UID (above).
attesteraddressLender’s on-chain signing wallet. Must be currently ACTIVE in LenderRegistry.
recipientaddressConventionally the merchant’s wallet or 0x0 (subject identity is in subjectRootUid).
timeuint64Block-mined issuance time.
expirationTimeuint64Mirrors expiresAt.
revocationTimeuint640 if active.
revocablebooltrue.
databytesABI-encoded payload per the schema string above.

​
Lender-registry mirror (lenderCurrentStatus)

The reconciler sweeps every 6 hours and mirrors the current LenderRegistry status onto every ACTIVE Schema B row. A verifier reading the Droplinked API sees: 
{
  "status": "ACTIVE",
  "lenderCurrentStatus": "SUSPENDED",
  "lenderCurrentStatusAt": "2026-06-14T01:00:00Z"
}
The reconciler never auto-revokes. A Schema B attestation that’s still on-chain ACTIVE but issued by a now-SUSPENDED lender is honored or not per verifier policy. The MCP verify_credit_risk tool and the verifier API both expose this mirror.

​
Read via Droplinked API

curl -s https://apiv3.droplinked.com/v2/attestations/credit-risk/6a0001a08692425bd9fd571b | jq .

{
  "found": true,
  "chain": "base",
  "attestations": [
    {
      "attestationUid": "0xab12…cd34",
      "schemaUid": "0xbd65…c7bd",
      "lenderId": "crediblex-uae",
      "issuerWallet": "0x…",
      "creditTier": "T2",
      "maxCreditLineUsdCents": 25000000,
      "termDays": 90,
      "rateBps": 1250,
      "methodologyHash": "0x…",
      "issuedAt": "2026-06-14T12:00:00Z",
      "expiresAt": "2026-12-14T12:00:00Z",
      "status": "ACTIVE",
      "lenderCurrentStatus": "ACTIVE",
      "lenderCurrentStatusAt": "2026-06-14T18:00:00Z"
    }
  ]
}

​
Read via viem (TypeScript)

import { createPublicClient, http, parseAbi, decodeAbiParameters } from "viem";
import { base } from "viem/chains";

const EAS = "0x4200000000000000000000000000000000000021" as const;
const SCHEMA_B = "0xbd652f94a034edea8635b1f87d05f2b33b23c0243430c2dae91469103921c7bd" as const;

const client = createPublicClient({ chain: base, transport: http() });

const easAbi = parseAbi([
  "function getAttestation(bytes32 uid) view returns (tuple(bytes32 uid, bytes32 schema, uint64 time, uint64 expirationTime, uint64 revocationTime, bytes32 refUID, address recipient, address attester, bool revocable, bytes data))",
]);

const uid = "0x…"; // UID from /v2/attestations/credit-risk/:merchantId
const att = await client.readContract({
  address: EAS,
  abi: easAbi,
  functionName: "getAttestation",
  args: [uid],
});
if (att.schema !== SCHEMA_B) throw new Error("not a Schema B attestation");

const [
  subjectRootUid,
  creditTier,
  maxCreditLineUsdCents,
  termDays,
  rateBps,
  methodologyHash,
  expiresAt,
] = decodeAbiParameters(
  [
    { name: "subjectRootUid", type: "string" },
    { name: "creditTier", type: "uint8" },
    { name: "maxCreditLineUsdCents", type: "uint64" },
    { name: "termDays", type: "uint32" },
    { name: "rateBps", type: "uint32" },
    { name: "methodologyHash", type: "bytes32" },
    { name: "expiresAt", type: "uint256" },
  ],
  att.data,
);

const tierLabel = ["T0", "T1", "T2", "T3"][Number(creditTier)];
const isActiveOnChain =
  att.revocationTime === 0n && BigInt(Math.floor(Date.now() / 1000)) < expiresAt;

console.log({ subjectRootUid, tier: tierLabel, maxCreditLineUsdCents, termDays, rateBps, isActiveOnChain });

​
Read via ethers (TypeScript)

import { JsonRpcProvider, Contract, AbiCoder } from "ethers";

const EAS = "0x4200000000000000000000000000000000000021";
const SCHEMA_B = "0xbd652f94a034edea8635b1f87d05f2b33b23c0243430c2dae91469103921c7bd";

const provider = new JsonRpcProvider("https://mainnet.base.org");
const eas = new Contract(
  EAS,
  [
    "function getAttestation(bytes32 uid) view returns (tuple(bytes32 uid, bytes32 schema, uint64 time, uint64 expirationTime, uint64 revocationTime, bytes32 refUID, address recipient, address attester, bool revocable, bytes data))",
  ],
  provider,
);

const uid = "0x…";
const att = await eas.getAttestation(uid);
if (att.schema.toLowerCase() !== SCHEMA_B) throw new Error("schema mismatch");

const decoded = AbiCoder.defaultAbiCoder().decode(
  ["string", "uint8", "uint64", "uint32", "uint32", "bytes32", "uint256"],
  att.data,
);

const [subjectRootUid, creditTier, maxCreditLineUsdCents, termDays, rateBps, methodologyHash, expiresAt] = decoded;
console.log({ subjectRootUid, creditTier, maxCreditLineUsdCents, termDays, rateBps, expiresAt });

​
Read via Cast (Foundry)

cast call 0x4200000000000000000000000000000000000021 \
  "getAttestation(bytes32)((bytes32,bytes32,uint64,uint64,uint64,bytes32,address,address,bool,bytes))" \
  0xab12ffffffffffffffffffffffffffffffffffffffffffffffffffffffffcd34 \
  --rpc-url https://mainnet.base.org

# Decode the schema payload from the `data` field of the above:
cast abi-decode \
  "x(string,uint8,uint64,uint32,uint32,bytes32,uint256)" \
  0x…

​
Indexer access (EAS GraphQL)

All Schema B attestations issued by a specific lender wallet, newest first: 
query LenderBook($wallet: String!) {
  attestations(
    where: {
      schemaId: { equals: "0xbd652f94a034edea8635b1f87d05f2b33b23c0243430c2dae91469103921c7bd" }
      attester: { equals: $wallet }
    }
    orderBy: { time: desc }
    take: 100
  ) {
    id
    time
    revocationTime
    expirationTime
    recipient
    data
  }
}
All Schema B attestations for a merchant — there is no on-chain index on subjectRootUid; for scale, query the Droplinked API (GET /v2/attestations/credit-risk/:merchantId) which serves an indexed projection.

​
Trust assumptions

A Schema B attestation is authoritative if and only if:
  1. The on-chain schema matches the mainnet UID above.
  2. The on-chain attester is currently ACTIVE in LenderRegistry. Check via GET /v2/lenders/:lenderId or read the Droplinked-API envelope’s lenderCurrentStatus mirror.
  3. revocationTime == 0 AND expirationTime > now.
  4. The methodologyHash resolves to an ACTIVE row in the methodology registry for that lender — the lender’s published methodology document is the explanation surface for the verdict.
A Schema B attestation issued by a lender that has since been SUSPENDED or ARCHIVED remains on-chain ACTIVE — the chain has no opinion on the lender’s current standing. The Droplinked reconciler exposes the current registry status via lenderCurrentStatus. Verifier-side policy decides whether to honor it. The agentic PM shadow protocol is explicit: this is a verifier decision, not a reconciler decision.