> ## Documentation Index > Fetch the complete documentation index at: https://docs.droplinked.com/llms.txt > Use this file to discover all available pages before exploring further. # Schema B — Credit-risk attestation > On-chain reference for the credit-risk schema. A registered lender's underwriting verdict on a merchant — credit tier, line ceiling, term, rate, methodology hash. 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 name** | `CreditRiskAttestation` | | **EAS revocable** | yes | | **Expiry semantics** | required (`expiresAt` is mandatory; lender re-underwrites at expiry) | | **Issued by** | A wallet currently `ACTIVE` in [`LenderRegistry`](/api-reference/public/lender-registry) | | **Subject** | Merchant (`subjectRootUid`) | | **MCP tool** | [`verify_credit_risk`](/agentic/mcp-server) | | **Verifier API** | `GET /v2/attestations/credit-risk/:merchantId` | | **Composite read** | [`GET /v2/underwriting-signals/:merchantId`](/api-reference/public/underwriting-signals) | ## Network & UIDs | Network | EAS contract | Schema UID | Explorer | | ------------ | -------------------------------------------- | ----------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Base mainnet | `0x4200000000000000000000000000000000000021` | `0xbd652f94a034edea8635b1f87d05f2b33b23c0243430c2dae91469103921c7bd` | [basescan](https://basescan.org/address/0x4200000000000000000000000000000000000021) · [easscan schema](https://base.easscan.org/schema/view/0xbd652f94a034edea8635b1f87d05f2b33b23c0243430c2dae91469103921c7bd) | | Base Sepolia | `0x4200000000000000000000000000000000000021` | resolve via `chain` field on `/v2/attestations/credit-risk/:merchantId` | [sepolia.basescan](https://sepolia.basescan.org/address/0x4200000000000000000000000000000000000021) | 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 ``` | Field | Solidity type | Semantic | Mutability | | ----------------------- | ------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------- | | `subjectRootUid` | `string` | Subject anchor. Production form: `"merchant:"`. Post-rotation: `keccak256(entityType\|\|entityId)` bytes32 (legacy + new coexist during transition). | immutable per attestation | | `creditTier` | `uint8` | Resolved credit tier at issuance. Encoded T0=0 / T1=1 / T2=2 / T3=3. Snapshot from `CreditTierMappingService` at mint time. | immutable per attestation | | `maxCreditLineUsdCents` | `uint64` | Maximum credit line in USD cents (`getLineCeilingUsd × 100`). | immutable per attestation | | `termDays` | `uint32` | Quoted repayment term in days. DTO layer enforces 1-1800 (5y) before mint. | immutable per attestation | | `rateBps` | `uint32` | Quoted APR in basis points (`850` = 8.50%). | immutable per attestation | | `methodologyHash` | `bytes32` | `keccak256` of the lender's published underwriting methodology document. Cross-references the [methodology registry](/api-reference/public/methodology-registry). | immutable per attestation | | `expiresAt` | `uint256` | Unix seconds. Required; a re-underwrite mints a new attestation. | immutable per attestation | EAS envelope fields: | Envelope field | Type | Semantic | | ---------------- | --------- | ---------------------------------------------------------------------------------------- | | `uid` | `bytes32` | Attestation UID. | | `schema` | `bytes32` | Schema UID (above). | | `attester` | `address` | Lender's on-chain signing wallet. Must be currently `ACTIVE` in `LenderRegistry`. | | `recipient` | `address` | Conventionally the merchant's wallet or `0x0` (subject identity is in `subjectRootUid`). | | `time` | `uint64` | Block-mined issuance time. | | `expirationTime` | `uint64` | Mirrors `expiresAt`. | | `revocationTime` | `uint64` | `0` if active. | | `revocable` | `bool` | `true`. | | `data` | `bytes` | ABI-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: ```json theme={null} { "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 ```bash theme={null} curl -s https://apiv3.droplinked.com/v2/attestations/credit-risk/6a0001a08692425bd9fd571b | jq . ``` ```json theme={null} { "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) ```ts theme={null} 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) ```ts theme={null} 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) ```bash theme={null} 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) * Base mainnet: [https://base.easscan.org/graphql](https://base.easscan.org/graphql) * Base Sepolia: [https://base-sepolia.easscan.org/graphql](https://base-sepolia.easscan.org/graphql) **All Schema B attestations issued by a specific lender wallet, newest first:** ```graphql theme={null} 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`](/api-reference/public/lender-registry). 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](/api-reference/public/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. ## Related * [Trust Fabric overview](/concepts/trust-fabric) * [Schemas overview](/api-reference/public/eas-schemas/overview) * [Lender Registry Lookup](/api-reference/public/lender-registry) * [Methodology Registry Lookup](/api-reference/public/methodology-registry) * [`/v2/underwriting-signals/:merchantId`](/api-reference/public/underwriting-signals) — composite Schema B + C read