Request an architecture briefing

Post-close QC — the worked example

The mandate

Post-close quality control is not optional. Fannie Mae Selling Guide D1-3-01 requires a lender to select, for post-closing QC review, "a minimum of 10% of the loans that it originates or acquires using a random selection methodology" (quoted from the Selling Guide; verified 2026-08-17). That floor exists because human reperformance costs real money — whole departments or outsourced audit spend, file by file. The incumbent answers are mortgage QC software that manages the sample workflow and audit-services firms that supply the reviewers. Sampling itself is a cost compromise, not a method anyone would choose with free review.

The walk

What a governed QC reperformance looks like inside the kernel, step by step: a named actor claims the file; the kernel records every extraction with the exact document and page it read — the schema refuses an unanchored extraction; checks run against the guideline version live that day, and the seal captures that version, so "show me the rule as it read that day" has an answer; a distinct checker — not the maker — resolves findings, because the database refuses a maker sealing its own work; the sealed result appends to a tamper-evident chain.

The architecture's design basis is the full population — every file, not a sample, each with its own evidence pack. Stated exactly: we built the architecture for that; it is not a delivered customer result, and the AI review layer that would produce it at scale does not yet exist. The sealing architecture runs today; the AI judgment layer does not yet exist — see what runs today.

A design basis, not a delivered customer result.

The sealed pack

the finding, and the rationale it rests onwho judged — and the distinct actor who approvedguideline identifier and the exact version live at judgment timedocument and page for every extraction citedderived by the kernel, never self-reportedappend-only entry; prior-entry hash carried forward

Origination document review

The judgment
Whether the documents in a purchase or refinance file are the right documents, read correctly — income, assets, identity, occupancy — against the lender's underwriting rules. The same loan file review shape covers HELOC and home equity loan files; only the rules content changes.
Who attests it today
Underwriters and processors, document by document, largely by stare-and-compare.
What a sealed record of it contains
Each extraction anchored to its source page; each conclusion tied to the rule version applied; maker and approver distinct; the whole file's review appended to the chain.
What stays honest
Same kernel shape — surface-specific regulatory facts appear only with their own verified source.

Underwriting conditions

The judgment
Whether the documents that came back actually satisfy a condition attached at approval.
Who attests it today
Underwriting-ops staff clearing conditions in the LOS queue, one at a time, under cycle-time pressure.
What a sealed record of it contains
The condition, the evidence that cleared it with document-and-page anchors, the rule version applied, and the distinct approver — attested, not just marked done.
What stays honest
Same kernel shape — surface-specific regulatory facts appear only with their own verified source.

Closing and funding checks

The judgment
Whether the file is complete and consistent at the moment money moves — the last look, under the most time pressure. This is where the title and settlement side of the table sits in the same kernel: title commitment review (whether the commitment's requirements and exceptions actually cleared), settlement and closing document verification, escrow reconciliation.
Who attests it today
Closers, funders, and settlement or escrow agents working checklists against the clock.
What a sealed record of it contains
The checks run, the documents they read, the versions they applied, the distinct approval — sealed before funding, inspectable after.
What stays honest
Same kernel shape — these name where the judgment shape applies, not shipped features; surface-specific regulatory facts appear only with their own verified source.

Servicing transfers

The judgment
Whether what boards onto a new servicer's system matches what both sides reviewed and agreed — data, documents, status — for first mortgages and home equity lines alike.
Who attests it today
Boarding and transfer teams reconciling files between systems.
What a sealed record of it contains
What the transfer team reviewed at boarding, under which rules, by whom, with a distinct approver — in a form the next holder can check rather than take on faith.
What stays honest
Same kernel shape — surface-specific regulatory facts appear only with their own verified source.

Audit and disclosure response

The judgment
Answering the examiner's question — what did your AI do, on which files, under what safeguards — with evidence rather than testimony.
Who attests it today
Compliance teams assembling responses from workflow databases and memos.
What a sealed record of it contains
The complete, append-only account of every recorded judgment — who, which rule version, which document, at what cost — built for the asker to recompute, not to take from the answerer on trust. Fannie Mae's LL-2026-04 makes this a live obligation across origination and servicing; the details are in the explainer.
What stays honest
Same kernel shape — the LL-2026-04 citation carries its verification on its own page; no other surface borrows it.