> ## 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.

# Underwriting MCP Tools

> Composite read tools for lender-agent / merchant-portal flows: get_underwriting_signals, get_upgrade_preview, verify_methodology.

Three MCP tools wrapping the underwriting layer of the [trust fabric](/concepts/trust-fabric). Together they cover the "should I underwrite + at what tier" decision in one round trip, the merchant-facing aspirational roadmap, and the forensic-chain step that audits the underwriting methodology cited on a Schema B attestation.

## `get_underwriting_signals`

Composite envelope that bundles into ONE call what previously took 3-4 separate per-axis verifier calls: Schema B latest-per-lender + Schema C merchant-wide rollup + CreditTier upgrade preview + a `summary` block.

```typescript theme={null}
const signals = await mcp.callTool('get_underwriting_signals', {
  merchantId: '6a207db0d29923bffaa983ca',
});
```

```json theme={null}
{
  "merchantId": "6a207db0d29923bffaa983ca",
  "creditRisk": {
    "hasAny": true,
    "activeCount": 2,
    "maxObservedTier": "T3",
    "latestPerLender": [
      { "lenderId": "crediblex-uae", "creditTier": "T2",
        "maxCreditLineUsdCents": 5000000,
        "lenderCurrentStatus": "ACTIVE", "status": "ACTIVE", ... },
      { "lenderId": "valinor-vault", "creditTier": "T3",
        "maxCreditLineUsdCents": 10000000,
        "lenderCurrentStatus": "SUSPENDED", "status": "ACTIVE", ... }
    ]
  },
  "repaymentHistory": {
    "hasAny": true,
    "perLenderCount": 2,
    "merchantWide": {
      "totalSettlements": 17, "totalOnTime": 13,
      "totalLate": 3, "totalDefaults": 1,
      "trailingTwelveMonthDefaults": 1,
      "mostRecentSettlementAt": "2026-06-05T..."
    }
  },
  "upgradeEligibility": {
    "observedTier": "T2",
    "nextTierTarget": "T3",
    "onTimeSettlementsNeeded": 8,
    "blockingDefaultCount": 1
  },
  "summary": {
    "anchorTier": "T3",
    "totalActiveCreditLineUsdCents": 15000000,
    "reliabilityScore": 76
  }
}
```

### Watch the `summary` block — it's load-bearing

| Field                           | Why it matters                                                                                                                                            |
| ------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `anchorTier`                    | `max(observed-from-repayment, already-issued)` — a lender never under-prices a merchant who has already proven a higher tier on a different lender's book |
| `totalActiveCreditLineUsdCents` | Sum of `maxCreditLineUsdCents` across all ACTIVE Schema B attestations                                                                                    |
| `reliabilityScore`              | `onTimeSettlements / totalSettlements * 100` (0-100); `null` when no settlement history yet                                                               |

### Watch `latestPerLender[].lenderCurrentStatus`

When the attestation `status: ACTIVE` but `lenderCurrentStatus: SUSPENDED` / `ARCHIVED` / `UNKNOWN`, the on-chain attestation is still valid but the issuer has been de-listed in the LenderRegistry. **Verifier-side policy decides** whether to honor.

Wraps: [`GET /v2/underwriting-signals/:merchantId`](/api-reference/public/underwriting-signals).

## `get_upgrade_preview`

Aspirational roadmap to higher credit-tier ceilings. Use this on merchant-portal flows asking "what does it take to climb?"

```typescript theme={null}
const preview = await mcp.callTool('get_upgrade_preview', {
  merchantId: '6a207db0d29923bffaa983ca',
});
```

```json theme={null}
{
  "observedTier": "T1",
  "nextTierGap": {
    "targetTier": "T2",
    "onTimeSettlementsNeeded": 1,
    "blockingDefaultCount": 0,
    "guidance": "Settle 1 more on-time to reach T2 ceiling."
  },
  "topTierGap": {
    "targetTier": "T3",
    "onTimeSettlementsNeeded": 8,
    "blockingDefaultCount": 0,
    "guidance": "Settle 8 more on-time to reach T3 (top ceiling)."
  }
}
```

**Aspirational, not a promise.** The actual issued tier depends on the lender's base tier mapping (revenue + inventory + sales-efficiency signals). This tool shows the *floor* a merchant can earn through repayment performance.

Tier ladder:

| Tier | Required                     | Blocks                     |
| ---- | ---------------------------- | -------------------------- |
| `T1` | Default — every new merchant | —                          |
| `T2` | 3+ on-time settlements       | Lifetime defaults > 0      |
| `T3` | 10+ on-time settlements      | Trailing-12mo defaults > 0 |

When the merchant reaches T3 both `nextTierGap` and `topTierGap` are `null`.

Wraps: [`GET /v2/merchant/credit-tier/upgrade-preview/:merchantId`](/api-reference/public/upgrade-preview).

## `verify_methodology`

Look up a lender's underwriting methodology. Two modes:

```typescript theme={null}
// Active mode — no methodologyHash
const active = await mcp.callTool('verify_methodology', {
  lenderId: 'crediblex-uae',
});

// Hash-lookup mode — supplied methodologyHash
const cited = await mcp.callTool('verify_methodology', {
  lenderId: 'crediblex-uae',
  methodologyHash: '0xabc...',
});
```

```json theme={null}
{
  "found": true,
  "lenderId": "crediblex-uae",
  "version": "2026.06.1",
  "methodologyHash": "0xabc...",
  "documentUrl": "https://crediblex.example.com/methodology-2026-06-1.pdf",
  "displayName": "CredibleX Inventory-Financing v2",
  "status": "ACTIVE",
  "effectiveAt": "2026-06-01T00:00:00Z",
  "supersededAt": null
}
```

**Use case**: a verifier consuming a Schema B credit-risk attestation reads the cited `methodologyHash` from the on-chain payload, calls this tool with that hash, downloads `documentUrl`, hashes it themselves, and compares. Any divergence flags methodology tampering.

Status enum:

| Status       | Meaning                                                                             |
| ------------ | ----------------------------------------------------------------------------------- |
| `ACTIVE`     | The currently-effective methodology — what new Schema B mints reference             |
| `SUPERSEDED` | An older version cited on legacy attestations; the lender has since updated         |
| `REVOKED`    | Operator pulled this methodology; existing attestations are flagged for re-issuance |

Wraps: `GET /v2/methodologies/:lenderId/active` and `GET /v2/methodologies/:lenderId/:methodologyHash`.

## Related

* [Trust Fabric overview](/concepts/trust-fabric) — full architecture
* [Lender Trinity MCP Tools](/agentic/lender-trinity-mcp-tools) — `verify_lender`, `recommend_lender`, `recommend_service_provider`
* [Forensic Chain Workflow](/concepts/forensic-chain) — how the tools compose for end-to-end attestation audit