mortgage-decision-record-audit-stream-reference

AGPL-3.0 reference implementation of mortgage-decision-record-audit-stream. Runs the Pacific Coast Mortgage Holdings × VendorR LoanDecision v5.2 trajectory end-to-end. 2 invariants: human-underwriter-required UNIVERSAL on every adverse-action-capable kind (PropTech is the ONLY Suite vertical with universal-not-scoped rule) + ECOA Reg B 30-day adverse-action notice clock per 12 CFR §1002.9.

Part of the Kinetic Gain Protocol Suite.

Sibling to fhir-resource-access-audit-reference, matter-decision-record-audit-stream-reference, grid-decision-record-audit-stream-reference, defense-decision-record-audit-stream-reference, government-decision-record-audit-stream-reference, financial-decision-record-audit-stream-reference, employment-decision-record-audit-stream-reference, and student-data-access-audit-stream-reference.

What this proves

PropTech is structurally distinct from every other Suite vertical:

1. Invariant #1 — human_underwriter_required UNIVERSAL on adverse-action-capable kinds, regardless of recommendation. Every other Suite vertical (FinTech, HR Tech, InsurTech, GovTech, HealthTech, DefenseTech, EnergyTech, LegalTech, EdTech) scopes the human-required rule to adverse outcomes only. PropTech doesn't — a clean approval still requires a named underwriter on file because the audit trail itself is what protects against post-hoc reverse-engineering claims under Fair Housing + Reg B.

2. Invariant #2 — ECOA Reg B 30-day adverse-action notice forward clock per 12 CFR §1002.9. When an outcome recommendation is adverse (decline, approve-with-conditions, counter-offer, withdraw-incomplete) AND the application has a completed_at timestamp, the lender has 30 days from completed-application to send written adverse-action notice. A different wall-clock pattern from the others: anchored on application completeness, not event timestamp.

Architecture

orchestrator.mjs (3 steps, escalating to recommendation)
   │
   ├─ requests access via mortgage-vault.mjs (universal underwriter + ECOA clock)
   │
   ├─ builds hash-chained event via event-builder.mjs (canonical-JSON SHA-256)
   │
   └─ emits to examples/pcm-loandecision-reference-stream.ndjson

verifier.mjs (independent, post-hoc)
   │
   ├─ chain integrity (each prev_hash = prior hash)
   ├─ invariant #1: universal human-underwriter on adverse-action-capable kinds
   └─ invariant #2: ECOA 30-day adverse-action notice clock

Run it

npm install && npm start
# → Built 3 events → examples/pcm-loandecision-reference-stream.ndjson
# → OK · 3 events · chain ✓ · 2 invariants ✓
npm test    # 9 unit tests

Canonical trajectory — Pacific Coast Mortgage Holdings × VendorR LoanDecision v5.2

Step	Event	Adverse-action-capable?	Underwriter required?
1	Application received (URLA 1003 stamp)	No (informational)	No
2	AI underwriting analysis produced (advisory)	No	No
3	Application decision recommended — approve-with-conditions	Yes	Yes — UNIVERSAL rule fires + ECOA 30-day notice sent within 2 days

approve-with-conditions counts as an adverse-action recommendation under Reg B because it changes terms from the original application — so both invariants fire on the same event.

Adverse-action-capable kinds (universal-rule set)

Kind	Why universal-not-scoped
application-decision-recommended	Could be decline/approve/counter — all need audit trail
refinance-decision-recommended	Same risk profile as origination
modification-decision-recommended	Loss-mit decisions trigger Reg X obligations
pricing-decision-recommended	Disparate-impact risk on rate-sheet outputs
appraisal-review-recommended	HVCC / appraiser-independence rules

Adverse-recommendation set (triggers ECOA clock)

decline · approve-with-conditions · counter-offer · withdraw-incomplete

A clean approve does not trigger Reg B's 30-day notice requirement (no adverse-action notice owed) but still triggers Invariant #1's universal underwriter requirement.

Vault denial scenarios (covered by tests)

Failure mode	Reason
Adverse-action-capable kind WITHOUT underwriter (even on approve)	"PropTech is the only Suite vertical with universal-not-scoped underwriter rule — Reg B + Fair Housing + RESPA risk profile"
Adverse recommendation without adverse_action_notice_sent_at	"ECOA Reg B 12 CFR §1002.9 — 30-day notice required"
ECOA notice sent >30 days after completed application	"ECOA 30-day adverse-action notice clock missed — sent N days after completed application"

Composes with

• mortgage-decision-record-audit-stream — the spec this implements
• respa-readiness-evidence-bundle — evidence bundle that ingests events
• title-chain-evidence-incident-card-profile — invariant failures become Incident Cards
• state-real-estate-ai-disclosure-tracker — 50-state lifecycle
• mls-data-access-vault-contract-profile — Decision Card vault contract
• Kinetic Gain Protocol Suite — umbrella

Compliance posture

Reference implementation readiness scaffolding for ECOA (Reg B) + RESPA (Reg X) + Fair Housing Act + TILA (Reg Z) + HMDA + state mortgage lending regimes. Does NOT constitute CFPB attestation, FHA insurance qualification, or substitute for a lender's own QC + fair-lending statistical analysis. The mock vault is in-memory — production deployments must integrate with the LOS (Encompass / Empower) + DU/LP underwriting engines + adverse-action notice generator. Per the standing Suite public-language guardrail: readiness · evidence · posture · controls · scaffolding — never "compliant" / "certified" without external attestation.

License

AGPL-3.0-only. Spec repos this depends on remain MIT.