Source: https://guthlabs.ai/docs/instruments/debt-service-coverage-ratio-dscr/implementation/

instrument implementation / implementation-contract

# Debt Service Coverage Ratio (DSCR) implementation

A source-bound implementation contract for Debt Service Coverage Ratio (DSCR); deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-083

**Effect**: Computation or source lookup only

## Input and validation requirements

A zero annual-debt-payment input makes the ratio undefined and must be rejected or surfaced as an explicit error. The pass/fail note also has an unstated threshold convention, and signed versus magnitude debt-service inputs can produce different DSCR values.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "net_operating_income_annual": 120000,
    "annual_debt_service": 80000
  },
  "expected_outputs": {
    "dscr": 1.5,
    "threshold_note": "No pass/fail determination; lender threshold is unspecified."
  },
  "working": "DSCR = NOI / Debt Service = 120000 / 80000 = 1.5."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/debt-service-coverage-ratio-dscr/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/debt-service-coverage-ratio-dscr/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/debt-service-coverage-ratio-dscr/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`